2) ELEMENTS, COMPOUNDS AND MIXTURES

Transcription

1 TOPIC PAPER 1 PAGE 1) MATTER 1 2) ELEMENTS, COMPOUNDS AND MIXTURES 6 3) ATOMIC STRUCTRE AND THE PERIODIC TABLE 13 4) STRUCTRE AND BONDING 27 5) METALS 35 6) HEATS AND RATES OF REACTION 49 7) CARBON AND ITS COMPOUNDS 58 8) ACIDS, BASES AND SALTS 61 9) THE ATMOSPHERE AND WATER 72 10) FUELS 82 11) ENZYMES 84 12) ORGANIC CHEMISTRY 82 13) ELECTROLYSIS ) QUALITATIVE ANALYSIS ) LABORATORY APPARATUS 113 1

2 1) MATTER 1. When water is warmed, what happens to its molecules? 2. Diagrams 1, 2 and 3 represent the three states of matter. For which states can diffusion be demonstrated by using simple laboratory apparatus? A 1 only B 1 and 2 C 2 and 3 D 1, 2 and 3 3. A solid metal is heated until it turns to vapour. The graph shows the temperature of the metal during this process. Which part of the graph shows the melting of the metal? 4. A shirt is stained with red ink from a pen. 2

3 The shirt is left to soak in a bowl of water. Which process causes the red colour to spread? A diffusion B evaporation C melting D neutralization 5. A sealed conical flask contains a liquid and its vapour, as shown. What happens when a molecule in the vapour enters the liquid? 6. Some students are asked to describe differences between gases and liquids. 3

4 Three of their suggestions are: Which suggestions are correct? A 1 only B 2 only C 3 only D 1, 2 and 3 7. A coloured liquid vaporises easily at room temperature. Some of the liquid is placed at the bottom of a sealed gas jar. Which diagram shows the appearance of the jar after several hours? 8. Measurements are made on some pure water. its boiling point, b.p. its freezing point, f.p. its ph Sodium chloride is now dissolved in the water and the measurements repeated. Which measured values change? 9. The diagram shows a chromatogram obtained from three sweets, X, Y and Z. 4

5 How many different red dyes are present in the sweets? A 1 B 2 C 3 D When steam at 100 o C condenses to water at 25 o C, what happens to the water molecules? A They move faster and closer together. B They move faster and further apart. C They move slower and closer together. D They move slower and further apart. 11. The melting points and boiling points of four substances are shown. Which substance is liquid at 100 o C? 12. At room temperature, in which substance are the particles furthest apart? A H 2 B H 2 O C Mg D MgO 13. In which change of state do the particles become more widely separated? A gas to liquid B gas to solid C liquid to gas D liquid to solid 14. In which of the following are the particles arranged in a regular pattern? A a gas B a liquid C a metal D a solution 15. The apparatus shown cannot be used to determine the melting point of sodium chloride, Na + Cl. 5

6 Why is this? 16. Blue copper (II) sulphate crystals are soluble in water. What has happened after one week? A crystallization B diffusion C distillation D filtration 6

7 2) ELEMENTS, COMPOUNDS AND MIXTURES 1. How can crystals be obtained from a hot, concentrated solution of a salt? A by adding cold water B by cooling and then filtering C by filtering only D by filtering and drying the residue 2. The diagrams show a cooling experiment and the results. What liquid could X be? 3. Some chemical compounds are purified by recrystallisation. What can be used to test the purity of the crystals? A melting point B colour of crystals C size of crystals D solubility 7

8 4. The diagram shows how to obtain pure water from seawater. Where do water molecules lose energy? 5. What could be the melting point and boiling point of water containing a dissolved impurity? 6. Which mixture can be separated by adding water, stirring and filtering? A barium chloride and sodium chloride B calcium carbonate and sodium chloride C copper and magnesium D ethane and ethene 7. The compound ethyl mercaptan, C 2 H 5 SH, has a very unpleasant smell. What is its relative molecular mass? 8. Water is formed when 48 g of oxygen combine with 6g of hydrogen. What mass of oxygen combines with 2 g of hydrogen? A 12 g B 16 g C 96 g D 144 g 8

9 9. The diagram shows a model of a molecule containing carbon, hydrogen and oxygen. How many atoms of each element are in the molecule? 10. Compound X does not dissolve in water, does not react with water, is used to control soil acidity. What is X? A calcium carbonate B calcium chloride C calcium hydroxide D calcium oxide 11. Which formula represents a compound containing three atoms? A HNO 3 B H 2 O C LiF D ZnSO Which compound contains three elements? A ethanol B ethane C methane D poly (ethene) 9

10 13. When hydrated copper (II) sulphate is heated in the apparatus shown, solid X and liquid Y are produced. Which changes are noticed when liquid Y is added to cold solid X? 14. Three mixtures are made. The mixtures are heated strongly. Which of the elements C, Cu and Mg are reactive enough to reduce the iron oxide to iron? A C and Cu only B C and Mg only C Cu and Mg only D C, Cu and Mg 10

11 15. The diagrams show the growth of four plants. Which element is acting as a fertiliser? A Cl B N C Na D S 16. In which reaction does reduction of the underlined substance take place? 11

12 17. A student wishes to extract a coloured solution from some berries to make an indicator solution. Which of the listed instructions should the student follow? A 1, 2 and 4 B 1, 3 and 4 C 2, 3 and 5 D 2, 4 and A substance X is heated in an evaporating basin until there is no further change. What could X be? A copper B copper (II) carbonate C copper (II) oxide D hydrated copper (II) sulphate 19. For which compound is the formula correct? 20. Which method can be used to obtain crystals from aqueous copper (II) sulphate? A chromatography B electrolysis C evaporation D neutralisation 12

13 21. A coin is dissolved in an acid. Chromatography is used to test the solution formed. The diagram shows the chromatogram obtained. What is the coin made from? A a metal element B a non-metal element C a mixture of metals D a mixture of non-metals 22. Two reactions involving water are shown. Which of these reactions are reversible by heating? 23. The diagram shows three balloons held by children. Which of the balloons float up into the air when the children let go? A P only B P and R only C Q only D Q and R only 13

14 3) ATOMIC STRUCTRE AND THE PERIODIC TABLE 1. The symbol of an element is 45 21Sc. How many electrons does one atom of this element contain? A 21 B 24 C 45 D The diagram shows the electronic structure of an atom. What is the number of protons in the nucleus? A 2 B 3 C 8 D Which number in the table is 1? 4. What is the electronic structure of an atom with a proton number 5 and a nucleon number 11? A 1, 8, 2 B 2, 8, 1 C 2, 3 D 3, 2 14

15 5. What changes when an ion is made from an atom? A the number of electrons only B the number of neutrons only C the number of protons only D the number both of protons and of neutrons 6. Strontium, Sr, is a metal that forms an ionic chloride SrCl 2. Sulphur, S, is a non-metal that forms a covalent chloride SCl 2. Which compound is likely to have the higher melting point (m.p.) and which is more soluble in water? 7. The relative atomic mass of oxygen is 16 and that of hydrogen is 1. This means that (i) of oxygen has the same mass as (ii) of hydrogen. Which words correctly complete the gaps? 8. Magnesium, on the left of Period Two of the Periodic Table, is more metallic than chlorine on the right of this Period. Why is this? Magnesium has A fewer electrons. B fewer protons. C fewer full shells of electrons. D fewer outermost electrons. 15

16 9. A student is asked to complete two sentences. Metallic and non-metallic elements are classified in the (i) This can be used to (ii) the properties of elements. Which words correctly complete the gaps? 10. The table shows the electronic structures of four elements. Which element is a noble gas? 11. The diagrams show four particles. Which two diagrams show atoms that are isotopes of each other? A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4 16

17 12. Eight elements are numbered in the diagram of a Periodic Table. Which numbers represent two relatively soft metals in the same group? A 1 and 2 B 3 and 4 C 5 and 6 D 7 and The proton number of helium is 2. What information does this give about helium? A Its atom has two electrons. B Its atom is twice as heavy as a hydrogen atom. C It is a Group II element. D Its molecule has two atoms. 14. The table gives information about four elements. Which element could be in Group I in the Periodic Table? 15. Hydrogen and helium have isotopes, as shown. In which of these isotopes does the nucleus have twice as many neutrons as protons? 17

18 16. The diagram shows a light bulb. Why is argon used instead of air in the light bulb? A Argon is a good conductor of electricity. B Argon is more reactive than air. C The filament glows more brightly. D The filament lasts for a longer time. 17. How are the electrons arranged in a neon atom, Ne, and a sodium ion, Na +? 18

19 18. Which diagram shows an atom in the same group of the Periodic Table as sodium? 19. When propane is burned, carbon dioxide and water are formed, as shown. Which values of r and s balance the equation? 20. Metals can be joined together by welding them at a high temperature. Why is an argon atmosphere often used? A Argon has a low density. B Argon is colourless. C Argon is inexpensive. D Argon is unreactive. 21. Which information about an element can be used to predict its chemical properties? A colour of its compounds B density C melting point D position in the Periodic Table 22. The table shows the nucleon numbers and proton numbers of some atoms. How many are atoms of non-metallic elements? A 1 B 2 C 3 D 4 19

20 23. The diagram shows part of the Periodic Table. Which statement about elements X, Y and Z is correct? The proton number of X is A seven less than that of Z. B three less than that of Z. C one less than that of Y. D sixteen less than that of Y. 24. Two isotopes of helium are Which two diagrams show the arrangement of particles in these two isotopes? 20

21 25. The chemical properties of an element depend mainly on the number of A electrons in the innermost shell. B electrons in the outermost shell. C fully occupied shells of electrons. D partly occupied shells of electrons. 26. Which row gives the outer electronic shell of fluorine and of neon? 27. The electronic configuration of an ion is What could this ion be? 28. What is the colour of liquid bromine and of the aqueous bromide ion? 29. What do the nuclei in a hydrogen molecule contain? A electrons and neutrons B electrons and protons C neutrons only D protons only 21

22 30. An element X is in Group III of the Periodic Table. Which property of X can be predicted from this fact? A the charge on an ion of X B the colour of the ion of X C the melting point of X D the relative atomic mass, Ar, of X 31. The table compares the properties of Group I elements with those of transition elements. Which entry in the table is correct? 32. Caesium is near the bottom of Group I of the Periodic Table. What is the correct description of caesium? 33. Which statements about isotopic atoms of the same element are correct? 22

23 34. Which diagram shows a positively charged ion? 35. The equation shows the reaction that occurs when ethanol burns in air. Which values of x, y and z are needed to balance this equation? 36. Which process does not involve either oxidation or reduction? A burning methane in the air B extracting iron from hematite C heating copper (II) oxide with carbon D reacting sodium carbonate with dilute hydrochloric acid 23

24 37. The table shows some properties of four gases. Which gas is most suitable for filling weather balloons? 38. A data book gives the following information about an element. Where is the element likely to be found in the Periodic Table? A Group 0 B Group I C Group VII D transition elements 39. Calcium, on the left of Period Three of the Periodic Table, is more metallic than bromine on the right of this Period. Why is this? Calcium has A fewer electrons. B fewer protons. C fewer full shells of electrons. D fewer outer shell electrons. 40. Five elements have proton numbers 10, 12, 14, 16 and 18. What are the proton numbers of the three elements that form oxides? A 10, 12 and 14 B 10, 14 and 18 C 12, 14 and 16 D 14, 16 and 18 24

25 41. Which numbers are added to give the nucleon number of an ion? A number of electrons + number of neutrons B number of electrons + number of protons C number of electrons + number of protons + number of neutrons D number of protons + number of neutrons 42. Which change to an atom occurs when it forms a positive ion? A It gains an electron. B It gains a proton. C It loses an electron. D It loses a proton. 43. Element X is at the left-hand side of the Periodic Table. Which line in the table shows the correct type and property of the oxide of X? 44. Element X forms an acidic, covalent oxide. Which row in the table shows how many electrons there could be in the outer shell of an atom of X? 45. Which atom has twice as many neutrons as protons? 46. Which number is different for isotopes of the same element? A number of electrons B number of full shells C number of nucleons D number of protons 25

26 47. The equation shows the reaction between a halogen and aqueous bromide ions. Which words should be written in gaps 1, 2 and 3? 48. A student is asked to complete two sentences. Metallic and non-metallic elements are classified in the 1. This can be used to 2 the properties of elements. Which words correctly complete the gaps? 49. The table shows the electronic structures of four atoms. Which two atoms combine to form an ionic compound? A W and X B W and Y C X and Y D X and Z 26

27 50. An element does not conduct electricity but it does exist as diatomic molecules. In which area of the Periodic Table is the element to be found? 51. Which properties of helium explain its use in filling balloons? 27

28 4) STRUCTRE AND BONDING 1. Which substance is a good conductor of electricity when solid? A a halogen B a metal C a plastic D a salt 2. The diagrams show the structures of two forms, X and Y, of a solid element. What are suitable uses of X and Y, based on their structures? 3. Which compound has the largest relative molecular mass, Mr? A CO 2 B NO 2 C SiO 2 D SO 2 4. Carbon and chlorine form a chloride. What is the formula of this chloride? A CCl 2 B CCl 4 C CaCl 2 D CaCl 4 5. Which compound has ionic bonds? A hydrogen chloride B methane C sodium chloride D water 28

29 6. What is the formula of copper (II) oxide and of sulphur hexafluoride? 7. The diagrams show models of molecules. Which molecules could the above models represent? 8. An inert gas X is used to fill weather balloons. Which descriptions of X are correct? 29

30 9. Which of the following can be used as a lubricant? 10. Which element is a solid non-metal? 11. The diagrams show the bonding in three covalent molecules. Which of these molecules combine to form ammonia? A 1 and 2 B 1 and 3 C 2 and 3 D 1, 2 and Which properties does a Group VI element have? 13. The electronic structure of an element is shown. 30

31 Which diagram shows the electronic structure of another element in the same group in the Periodic Table? 14. In the diagrams, circles of different sizes represent atoms of different elements. Which diagram can represent hydrogen chloride gas? 15. How many electrons are shared between the atoms in a molecule of methane, CH 4, and in a molecule of water, H 2 O? 31

32 16. The lead in a pencil is made of a mixture of graphite and clay. If the percentage of graphite is increased, the pencil slides across the paper more easily. Why is this? A Graphite conducts electricity. B Graphite is a form of carbon. C Graphite is a lubricant. D Graphite is a non-metal. 17. Which statement about gaseous hydrogen chloride and solid potassium chloride is correct? A Hydrogen chloride is covalent but potassium chloride is ionic. B Hydrogen chloride is ionic but potassium chloride is covalent. C They are both covalent compounds. D They are both ionic compounds. 18. The diagram shows the structure of hydrogen peroxide. What is the total number of electrons used for bonding in this molecule? A 3 B 4 C 6 D In the molecules CH 4, HCl and H 2 O, which atoms use all of their outer shell electrons in bonding? A C and Cl B C and H C Cl and H D H and O 20. The rows P, Q and R in the table show three pairs of structures. 32

33 Which pair or pairs are isotopes? A P only B P and Q only C Q only D Q and R only 21. For which compound is the formula correct? 22. The diagrams show the molecules of three elements. Which of these elements are present in water? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and The diagram shows the positions of some elements in the Periodic Table. 33

34 Which elements form ionic bonds with oxygen? A W only B W and X only C Y only D Y and Z only 24. The diagram shows an outline of part of the Periodic Table. Which two elements could form a covalent compound? A W and X B W and Y C X and Y D X and Z 25. Magnesium and sulphur each form a chloride. What could be the formulae of these chlorides? 26. A gas has the molecular formula NOCl. 34

35 Which diagram could show molecules of the pure gas NOCl? 5) METALS 35

36 1. The diagram shows an electric heater. Which method would be used to plate the chromium on to the steel? A alloying B electrolysis C galvanizing D oxidation 2. The table shows some properties of four materials. Which of these materials are most suitable to make the pins and the case of an electric plug? Pins Case A W X B X Z C Y W D Z Y 3. The following items are all made from metals. 36

37 Which items are made from stainless steel? A aircraft bodies B drink cans C knives and forks D motor car bodies 4. Which substance reacts with calcium to form a salt? A hydrochloric acid B oxygen C sodium hydroxide D water 5. The proton numbers of four elements are shown. Which element is a metal? 6. Zinc reacts with steam to form zinc oxide and hydrogen. Zn + H 2 O ZnO + H 2 During the reaction, which substance is oxidised? A hydrogen B water C zinc D zinc oxide 7. Hydrochloric acid is used to clean metals. The acid reacts with the oxide layer on the surface of the metal, forming a salt and water. Which word describes the metal oxide? A alloy B base C element D indicator 8. Which raw materials are used in the manufacture of iron? A bauxite and lime B bauxite and limestone C haematite and lime D haematite and limestone 9. Which material is an alloy that contains a non-metallic element? A brass B haematite C manganese D steel 10. The proton numbers of four elements are shown. 37

38 Which element is a metal? 11. The table shows the properties of four metals. Which metal would be the best to make the body of an aircraft? 12. The following items are all made from metals. Which items are made from stainless steel? A aircraft bodies B drink cans C knives and forks D motor car bodies 13. The bodies of aircraft are often made using aluminium. Which two properties of aluminium make it suitable for this purpose? 14. Which property do all metals have? 38

39 A They are hard. B They conduct electricity. C They form acidic oxides. D They react with water. 15. When hydrogen is passed over a heated metal oxide, the metal and steam are formed. What happens to the hydrogen and to the metal oxide? 16. The table gives information about the reactivity of three metals P, Q and R. What is the order of reactivity of P, Q and R? 17. Which methods can be used to prevent the rusting of an iron girder of a bridge? 39

40 18. Vanadium is a transition metal. What are its likely properties? 19. Element X forms an alloy. has a basic oxide. is below hydrogen in the reactivity series. What could X and the alloy be? 20. The diagram shows a method for changing a metal oxide into a metal. 40

41 Which oxide can be changed into a metal by using this method? A calcium oxide B copper (II) oxide C magnesium oxide D potassium oxide 21. The table shows properties of four elements. Which element is used to make aircraft bodies? 22. In an experiment, copper (II) oxide is changed to copper by a gas X. What happens to the copper (II) oxide and what is X? 23. Three metals X, Y, and Z are correctly placed in the reactivity series as shown. 41

42 most reactive least reactive potassium X sodium zinc Y iron copper Z How are X, Y and Z obtained from their ores? 24. The diagrams show the arrangement of electrons in three different atoms. Which atoms are metals? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and Which element is likely to be a transition metal? 26. Three metals are extracted as shown in the table. 42

43 What is the order of reactivity of the metals? 27. Haematite is reduced to iron in the blast furnace. What is X? A carbon B carbon dioxide C hydrogen D oxygen 28. Which object is least likely to contain aluminium? A a bicycle frame B a hammer C a saucepan D an aeroplane body 29. Aluminium is extracted from its oxide by electrolysis. Which words correctly complete the spaces? 30. An old railway carriage is being restored. Metal strips are secured on to the outside of the wooden carriage by means of screws. After a few weeks open to the wind and rain, the screws are heavily corroded but the metal strips are not. 43

44 Aluminium is more reactive than both steel and copper. Which two metals would give this result? 31. Part of the reactivity series is outlined below. Electrolysis is an expensive way of extraction. Which metal has to be extracted from its ore by electrolysis? A aluminium B copper C lead D iron 32. Which metal reacts quickly with cold water only when it is finely powdered? A calcium B copper C sodium D magnesium 33. Three different metals, Cu, Fe and Mg, are each added to an excess of dilute hydrochloric acid. The graph shows how rapidly hydrogen is given off. 44

45 Which metal gives which curve? 34. Which substance is a metal? 35. Which changes occur when impure iron is made into stainless steel. 36. The bodies of an aeroplane, a car and a wheelbarrow are made of metal. 45

46 37. Which chart could represent the composition of a galvanised roof? 38. Which two elements form an alloy when they are heated together? A chlorine and hydrogen B chlorine and zinc C copper and hydrogen D copper and zinc 39. Mild steel is an alloy of iron and carbon. How does the carbon affect the properties of mild steel? A The carbon makes the alloy a better conductor of electricity than iron. B The carbon makes the alloy harder than the iron. C The carbon makes the alloy softer than the iron. D The carbon stops the iron rusting. 40. Which property do all metals have? A Their densities are low. B Their melting points are high. C They act as catalysts. D They conduct electricity. 41. Three stages in making steel from iron ore are listed. 46

47 In which order do these stages occur? X carbon dioxide reacts with carbon Y basic oxides and oxygen are added Z hematite is reduced 42. Brass, an alloy of copper with another element, is used to make the contact pins of electrical plugs because it is harder than copper. In brass, the other element is a..x.. that..y.. with the copper. What are X and Y? 43. A student added dilute hydrochloric acid to four metals and recorded his results. Not all of his results are correct. Which two results are correct? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and Which of the following is made from stainless steel? 47

48 45. Copper, iron and zinc are all used to make things. Which of these three metals are also used in the form of alloys? 46. Which diagram shows a common use of stainless steel? 47. Aluminium is extracted from its oxide by electrolysis. To do so, the oxide is dissolved. Which substance is used to dissolve aluminium oxide and where is aluminium deposited during the electrolysis? 48

49 48. The statements are about metals and their oxides. Metals X electrons to form ions. The oxides of metals are Y. Which words correctly complete the statements? 49. The diagram shows apparatus used to test the reactivity of calcium, copper and magnesium with steam. Which metals react with steam to form hydrogen? 50. Which types of steel are used in chemical plants and machinery? 51. Which raw materials are used in the manufacture of iron? A bauxite and lime B bauxite and limestone C hematite and lime D hematite and limestone 49

50 6) HEATS AND RATES OF REACTION 1. Samples of four different substances are added to separate volumes of water. The temperature changes are measured. For which substance does exothermic reaction occur? 2. The diagram shows crystals of copper (II) sulphate, CuSO4. 5H 2 O, being heated. The crystals change colour. Which two terms describe this change? A endothermic and dehydration B endothermic and hydration C exothermic and dehydration D exothermic and hydration 3. A television news programme shows an explosion at a flour mill. What could have increased the risk of such an explosion? A adding salt to the flour B employing more staff in the mill C grinding the flour more finely D opening the windows 4. Which process is endothermic? A adding water to anhydrous copper(ii) sulphate B burning magnesium to make the oxide C heating water to make steam D neutralizing acidic industrial waste 50

51 5. The graphs show the mass of a beaker and its contents plotted against time. Which graph could represent the reaction between magnesium and dilute hydrochloric acid in an open beaker? 6. A student investigates the speed of the reaction between a lump of zinc and an acid at room temperature. Which other item of apparatus does the student need for this experiment? A Bunsen burner B measuring cylinder C stop clock D thermometer 7. In which process does an endothermic change take place? A combustion B evaporation C filtration D neutralisation 51

52 8. Potassium nitrate is a salt and dissolves in water in an endothermic process. What happens to the temperature and ph of the water as the salt dissolves? 9. The graph shows how the total volume of a gas given off from a reaction changes with time. In which time interval is least gas given off? 10. The table compares the strengths of the bonds for reactions of the type below. Which reaction is most exothermic? 52

53 11. A liquid X reacts with solid Y to form a gas. Which two diagrams show suitable methods for investigating the speed of the reaction? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and The diagram shows an experiment. Which metal would fill the syringe with 100 cm3 of gas in the shortest time? A 5 g of copper B 5 g of iron C 5 g of magnesium D 5 g of zinc 53

54 13. The solvent ethanol is produced by the fermentation of sugar, using yeast. Which graph correctly shows how the speed of fermentation changes with temperature? 14. In an experiment, a 2g lump of zinc and 2g of powdered zinc are added separately to equal volumes of dilute sulphuric acid. The solid line on the graph shows the volume of gas given off when the 2g lump is used. Which dotted line is obtained when the zinc is powdered? 54

55 15. The sign is used in some equations to show that a reaction can be reversed. Two incomplete equations are given. For which of these reactions can a sign be correctly used to complete the equation? 16. In which experiment is the rate of reaction between hydrochloric acid and calcium carbonate slowest? 17. Which process is endothermic? A burning hydrogen to form water B condensing steam to water C melting ice to form water D reacting sodium with water 55

56 18. Which diagrams show a process in which an exothermic change is taking place? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and In different experiments, 2 g of marble are added to 10 cm3 of hydrochloric acid. In which tube is the reaction fastest? 20. Equations for two changes P and Q are shown. Which of these changes are exothermic? 56

57 21. A liquid X reacts with solid Y to form a gas. Which two diagrams show suitable methods for investigating the speed of the reaction? 22. The elements H 2 and 235 U are both used as fuels. In these processes, the reactions are..1.. and..2.. oxidised. Which words correctly complete gaps 1 and 2? 57

58 23. Why does the powdering of calcium carbonate increase the speed of its reaction with an acid? A It increases the mass of calcium carbonate. B It increases the surface area of the calcium carbonate. C The powder becomes more concentrated. D The powder floats on top of the acid. 24. The diagram shows a speed of reaction experiment. Increasing the concentration of the acid and increasing the temperature both affect the speed of reaction. Which line of the table is correct? 25. The diagram shows one stage in the manufacture of nitric acid from ammonia. What could be the use of the platinum gauze in this process? A as a base B as a catalyst C as a filter D as a fuel 58

59 7) CARBON AND ITS COMPOUNDS 1. Which oxide can be reduced by heating it with carbon? A aluminium oxide B calcium oxide C copper(ii) oxide D potassium oxide 2. A student suggests three uses of calcium carbonate (limestone). 1 manufacture of cement 2 manufacture of iron 3 treating alkaline soils Which of these suggestions are correct? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 3. A steel works and a chemical works are built near to a city. The limestone buildings in the city begin to crumble. Which gas is most likely to cause this damage? A carbon dioxide B carbon monoxide C oxygen D sulphur dioxide 4. A newspaper article claims that carbon dioxide is formed as follows. 1 during respiration 2 when calcium carbonate reacts with hydrochloric acid 3 when methane burns in air Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 5. What are the products when limestone (calcium carbonate) is strongly heated? A calcium hydroxide and carbon dioxide B calcium hydroxide and carbon monoxide C calcium oxide and carbon dioxide D calcium oxide and carbon monoxide 59

60 6.Two processes are listed. 1 treating acidic soil with slaked lime 2 using limestone to extract iron In which of these processes is carbon dioxide produced? 7. Which of the oxides CaO, CuO and Na 2 O can be reduced by heating with carbon? A CaO only B CuO only C Na 2 O only D CaO, CuO and Na 2 O 8. Dolomite is a rock that contains magnesium carbonate. A piece of dolomite is heated strongly in air. Which word equation correctly describes the reaction that takes place? 9. In which process is carbon dioxide not formed? A blast furnace extraction of iron B burning of natural gas C heating lime D oxy-acetylene welding 10. A newspaper article claims that carbon dioxide is formed as follows. 1 during respiration 2 when calcium carbonate reacts with hydrochloric acid 3 when methane burns in air Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 60

61 11. In separate experiments, mixtures of CuO/C and of MgO/C are strongly heated in the apparatus shown. What happens to the limewater in these experiments? 12. The diagram shows a kiln used to heat limestone. What is the product and what waste gas is formed? 61

62 8) ACIDS, BASES AND SALTS 1. The incomplete equation shows a reaction. CuCO 3 + H 2 SO 4 products What are the products of this reaction? A copper(ii) oxide, sulphur dioxide, hydrogen B copper(ii) oxide, sulphur dioxide, water C copper(ii) sulphate, carbon dioxide, hydrogen D copper(ii) sulphate, carbon dioxide, water 2. Buildings made of calcium carbonate can react with acid rain. Which gas is formed as a result of this? A carbon dioxide B carbon monoxide C nitrogen dioxide D sulphur dioxide 3. Acidic waste gases from a factory are treated with substance X as shown. What is X? A polythene B slaked lime C vinegar D water 62

63 4. Which substance does not form copper(ii) sulphate with warm, dilute sulphuric acid? A copper B copper (II) carbonate C copper (II) hydroxide D copper (II) oxide 5. Water is added to a test-tube containing dilute sulphuric acid of ph 4. What could be the ph of the resulting solution? A 8 B 6 C 4 D 2 6. The diagram shows how the ph of an industrial waste changes when substance X is added to it. What is substance X? A coal B lime C salt D water 8. The equation shows what happens when hydrated copper(ii) sulphate is heated. CuSO 4.5H 2 O(s) CuSO 4 (s) + 5H 2 O(g) What can be deduced from the equation? A The hydrated copper (II) sulphate is oxidised. B The hydrated copper (II) sulphate is reduced. C The reaction is reversible. D There is no colour change. 9. Which two processes are involved in the preparation of magnesium sulphate crystals from dilute sulphuric acid and an excess of magnesium oxide? A decomposition and filtration B decomposition and oxidation C neutralisation and filtration D neutralisation and oxidation 63

64 10. Lead(II) oxide is reduced in the apparatus shown. How do the masses of parts X and Y of the apparatus change? 11. The ph values of four solutions are shown. Mixing combinations of these solutions can give a solution of ph 6. Which combination of solutions could not do this? A P and R B P and S C Q and R D R and S 64

65 12. The oxide Pb 3 O 4 reacts with dilute nitric acid to form lead(ii) nitrate, lead(iv) oxide and another product. What is the equation for this reaction? 13. The ph of some aqueous sodium hydroxide is measured. The solution is then distilled as shown. How do the ph values of the distillate and of the solution left in the flask compare with the original? 14. What is formed when calcium carbonate is heated? A calcium and carbon B calcium and carbon dioxide C calcium oxide and carbon D calcium oxide and carbon dioxide 65

66 15. Hydrochloric acid is used to clean a metal surface by removing the oxide layer on the metal. This is because hydrochloric acid has a..x.. ph and the metal oxide is..y.. What are X and Y? 16. A sample of acid rainwater (ph = 4) is passed down a glass column packed with marble chippings (calcium carbonate). The water coming from the bottom of the column is collected in a beaker. The ph is now 6. What causes the change in ph? A The acid has been filtered. B The acid has been neutralised. C The acid is made more concentrated. D The acid is precipitated. 66

67 17. The chart shows the colour ranges of four different indicators. Which indicator is blue in an acidic solution? 18. Which property does hydrochloric acid have? A It gives a pale blue precipitate with aqueous copper(ii) sulphate. B It gives a white precipitate with aqueous barium nitrate. C It releases ammonia from aqueous ammonium sulphate. D It releases hydrogen with zinc powder. 67

68 19. The apparatus shown can be used to prepare aqueous copper(ii) sulphate. What are substances X and Y? 20. In the experiment shown, the dilute sulphuric acid is run into the flask of aqueous barium hydroxide until the reaction is complete. Which processes occur in this reaction? 68

69 21. An excess of acid in the stomach causes indigestion that can be cured by an anti-indigestion tablet. What should the tablet contain to decrease the acidity? A an acidic substance B an alkaline substance C a neutral substance D Universal Indicator 22. A solution is made by adding sodium oxide to water. Which ph change can occur? 23. Which element has an oxide that forms a salt with an alkali? A N B Na C Ne D Ni 24. The diagram shows the results of a ph test on a sample of garden soil. What could be added to the soil to change its ph to 7? A ammonium nitrate B lime C sand D sodium chloride 69

70 24. Acids react with bases, carbonates and metals. Which of these reactions produce a gas? 25. Pure zinc sulphate can be prepared by adding an excess of either zinc carbonate or an excess of zinc hydroxide to dilute sulphuric acid. In which form are these zinc compounds used? 70

71 26. The diagram shows an experiment in which magnesium oxide powder is added to dilute hydrochloric acid. Which terms describe the experiment? 27. Which properties does an acid have? 1 reacts with ammonium sulphate to form ammonia 2 turns red litmus blue 71

72 28. Barium hydroxide is an alkali. It reacts with hydrochloric acid. What happens to the ph of a solution of hydrochloric acid as an excess of aqueous barium hydroxide is added? A The ph decreases from 14 but becomes constant at 7. B The ph decreases from 14 to about 1. C The ph increases from 1 but becomes constant at 7. D The ph increases from 1 to about The diagram shows the ph values of the soil in X and Y, two parts of the garden of a house. The house owner wishes to use lime to neutralise the soil in one part of the garden. To which part should the lime be added, and why? 72

73 30. The diagrams show two experiments, one to make barium chloride and the other to make barium sulphate. In each experiment, the acid is run into the conical flask until the resulting liquid has ph7. What are the next steps to obtain samples of the solid salts? 73

74 9) THE ATMOSPHERE AND WATER 1. Air is a mixture of gases. Which substance is present in the other gases and is also unreactive? A argon B carbon dioxide C hydrogen D water vapour 2. The diagram shows stages in producing drinking water. In which tank is chlorine added to the water? 3. Which of the following does not need a supply of oxygen in use? A breathing apparatus in hospitals B a fire extinguisher C an acetylene welding torch D a petrol engine 4. Which compound in polluted air can damage stonework and kill trees? A carbon dioxide B carbon monoxide C lead compounds D sulphur dioxide 74

75 5. To grow tomatoes, a fertiliser containing nitrogen, phosphorus and potassium is needed. For a good yield, the fertiliser should contain a high percentage of potassium. Which fertiliser is best for tomatoes? 6. In a car industry, approximately litres of water are required to produce a single car. This water does not need to be very pure. Which purification methods would be suitable and economic to use? 7. The diagram shows how water is purified. At which stage are bacteria in the water killed? 75

76 8. The pie-chart shows the composition of air. What are the gases in parts 1, 2 and 3 of the pie-chart? 9. A sample of clean, dry air is passed over hot copper until all the oxygen in the air reacts with the copper. The volume of air decreases by 30cm 3 What was the starting volume of the sample of air? A 60cm 3 B 100cm 3 C 150cm 3 D 300cm Which metallic element is needed in a complete fertiliser? A calcium B magnesium C potassium D sodium 76

77 11. Which substance is not a pollutant of clean air? A argon B carbon monoxide C nitrogen dioxide D sulphur dioxide 12. The apparatus shown is set up and left for a week. Where would the water level be at the end of the week? 13. An NPK fertiliser contains three elements required for plant growth. Which two compounds, when mixed, provide the three elements? A ammonium phosphate + potassium nitrate B ammonium sulphate + potassium nitrate C ammonium sulphate + sodium nitrate D sodium phosphate + potassium chloride 14. Which processes do not use oxygen? 1 burning natural gas 2 heating a room with an electric fire 3 welding apparatus A 1 only B 2 only C 3 only D 1, 2 and 3 77

78 15. The diagram shows how oxygen is used in welding. What is gas X? A acetylene B argon C neon D nitrogen 16. A candle is burned in a fixed volume of air. How do the percentages (%) of carbon dioxide and oxygen change? 17. The diagram shows ethanol burning inside a sealed jar. The mass of one gas in the jar does not change. Which gas is this? A carbon dioxide B nitrogen C oxygen D water vapour 78

79 18. Gas is released in all of the examples below. Which gas do they all produce? A carbon dioxide B hydrogen C methane D oxygen 19. Anhydrous calcium chloride is used as a drying agent. An alkaline solution of pyrogallol absorbs oxygen and carbon dioxide. Clean air is passed through the apparatus shown. Which gases are present in the air leaving the apparatus? 79

80 20. Which methods prevent rusting of iron? 21. What is the purpose of the fine sand filter in the purification of the water? A to allow particles to settle B to sort particles into layers C to trap large particles D to trap small particles 22. The diagram shows stages in the purification of water. Which stage uses chlorine? 80

81 23. The diagrams show experiments to investigate rusting of iron nails. In which test-tubes do the nails rust? A 1 only B 1 and 2 only C 1 and 3 only D 1, 2 and In experiments on rusting, some students are each given two metal objects to study. One student set up his apparatus as shown. Which objects rusted? 81

82 25. The diagram represents the composition of dry air. Which part shows the percentage of nitrogen in the air? 26. The diagram shows some uses of water in the home. For which of these uses is it important for the water to have been purified? A 1 only B 2 only C 3 only D 1, 2 and The listed pollutants are sometimes found in car exhaust fumes. 1 carbon monoxide 2 nitrogen oxides 3 sulphur dioxide Which of these pollutants are products of the combustion of the fuel? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 82

83 28. A shopkeeper stores iron nails in an airtight container, as shown in the diagram. The nails begin to rust after a few days. How can the rusting of the nails be prevented? A leave the lid off B put a drying agent in the jar C put the jar in a warm place D seal the jar in a bag 29. Two uses of oxygen are 1 burning acetylene in welding, 2 helping the breathing of hospital patients. Which of these uses form carbon dioxide? 83

84 10) FUELS 1. Which gas is produced by the incomplete combustion of coal? A carbon dioxide B carbon monoxide C nitrogen dioxide D sulphur dioxide 2. The diagram shows the sources of energy a country uses to generate electricity. What is the total percentage of fuels used which, when burned, could cause acid rain? A 20% B 80% C 90% D 100% 3. Which two fuels each produce both carbon dioxide and water when separately burned in air? A charcoal and hydrogen B charcoal and petrol C natural gas and hydrogen D natural gas and petrol 4. When it is used as a fuel, hydrogen combines with substance X. What is X? A carbon B methane C nitrogen D oxygen 5. Which two gases produced from the burning of petrol in motor vehicles contribute to the formation of acid rain? A carbon dioxide and carbon monoxide B carbon monoxide and sulphur dioxide C carbon monoxide and nitrogen dioxide D nitrogen dioxide and sulphur dioxide 84

85 6. Are hydrogen and uranium oxidised when used as a source of energy? 7. Coal, methane and hydrogen are burned as fuels. Which descriptions of this process are correct? 85

86 11) ENZYMES 1. Substance X does not react with dilute acid but substance Y does, forming a gaseous product. The graph shows the results of experiments with X, Y and dilute acid. What do these results show about X? 2. Which statement explains why iron is used as the catalyst in the manufacture of ammonia? A More ammonia is produced in a given time. B The catalyst is unchanged at the end of the reaction. C The catalyst neutralises the ammonia. D The purity of the ammonia is improved. 3. The decomposition of glucose, in aqueous solution, to form ethanol and carbon dioxide is catalysed by an enzyme in yeast. Which change increases the rate of this decomposition? A add more water to the solution B cool the solution C heat the solution to boiling point D heat the solution to 30 C 86

87 4. A solution of hydrogen peroxide releases oxygen slowly at room temperature. hydrogen peroxide. water + oxygen The diagrams show the effect of adding blood to the solution. What could be the reason for the observed change? A Blood contains an enzyme. B Blood contains water. C The hydrogen peroxide becomes more concentrated. D The hydrogen peroxide is neutralised by blood. 87

88 12) ORGANIC CHEMISTRY 1. What is the structure of the product of the catalytic addition of steam to ethene? 2. Which process is used at an oil refinery? A cracking B electrolysis C fermentation D neutralisation 3. Which statement is correct both for methane and for ethane? A They are alcohols. B They are alkenes. C They are in the same homologous series. D They can undergo addition polymerisation. 88

89 4. Which reaction is an example of the cracking of an alkane? A 3C 2 H 4 C 6 H 12 B C 6 H 14 6C + 7H 2 C C 6 H 12 + H 2 C6H14 D C 6 H 14 C 2 H 4 + C 4 H In ripe fruit, the conversion of sugars into alcohol can occur naturally. What is the name of this process? A addition B cracking C fermentation D polymerisation 6. The diagram shows a model of an organic compound. What is the name of this compound? A ethane B ethanoic acid C ethanol D ethene 7. Bitumen is a substance obtained from the fractional distillation of petroleum. What are the boiling points and the sizes of the molecules in bitumen? 89

90 8. Which hydrocarbons in the table are members of the same homologous series? A 1 and 2 B 1 and 3 C 3 and 4 D 1, 2, 3 and 4 9. Which of the molecules shown can be polymerised? 90

91 10. Which conditions are necessary to ferment sugar into ethanol? 11. Organic compounds may have names ending in ane, -ene, -ol or oic acid. How many of these endings indicate the compounds contain double bonds in their molecules? A 1 B 2 C 3 D Which compound is unsaturated and forms a neutral solution in water? 13. Which fraction produced by the distillation of petroleum is used as aircraft fuel? A bitumen B diesel C paraffin D petrol 14. Four fractions obtained from crude oil (petroleum) are listed below. Which fraction is paired with a correct use? 91

92 15. The diagram shows the structures of two compounds. The two compounds have similar chemical properties. Why is this? Their molecules have the same A functional group. B number of carbon atoms. C number of oxygen atoms. D relative molecular mass. 16. The structures of three compounds are shown. Why do these substances all belong to the same homologous series? A They all contain an even number of carbon atoms. B They all contain the same functional group. C They are all hydrocarbons. D They are all saturated. 17. The table shows some suggested reactions involving ethanol. Which suggestions about the reactants and products are correct? 92

93 18. The apparatus shows an experiment used to test gas X. The bromine solution quickly becomes colourless. What is the structure of gas X? 93

94 19. The diagram shows the manufacture of an important organic chemical X. What is X? A ethane B ethanol C methane D methanol 20. Which compound is ethanol? 21. What is petroleum? A an aircraft fuel B a central heating fuel C a mixture of carbohydrates D a mixture of hydrocarbons 22. Methanol and ethanol belong to the same homologous series. What does this mean? A Their molecules contain atoms only of carbon and hydrogen. B Their molecules have the same number of carbon atoms. C They have the same functional group. D They have the same relative molecular mass. 94

95 23. Which substances can be obtained by cracking hydrocarbons? A ethanol and ethene B ethanol and hydrogen C ethene and hydrogen D ethene and poly(ethene) 24. The apparatus shown may be used to study the products of fermentation. What is the purpose of the aqueous calcium hydroxide? A to absorb any excess of yeast B to condense the ethanol produced C to prevent air entering the system D to show that carbon dioxide is produced 25. Which two compounds have molecules in which there is a double bond? A ethane and ethanoic acid B ethane and ethanol C ethene and ethanoic acid D ethene and ethanol 26. Which substance is found in crude oil? A bitumen B ethanol C ethanoic acid D poly(ethene) 27. Which statement about a family of organic compounds describes an homologous series? All compounds in the family have the same A functional group. B physical properties. C relative molecular mass. D structural formula. 28. What is formed when ethane burns incompletely but not when it burns completely? A carbon dioxide B carbon monoxide C ethene D hydrogen 95

96 29. Which column describes ethane and which column describes ethene? A 1 (ethane) and 2 (ethene) B 1 (ethane) and 3 (ethene) C 2 (ethene) and 3 (ethane) D 3 (ethane) and 4 (ethene) 30. Which of the products C 12 H 24 and H 2 could be formed by cracking dodecane, C 12 H 26? 31. Some students are asked to draw the structure of propanol. Which diagram should the students draw? 96

97 32. Acetylene is an unsaturated hydrocarbon used with oxygen in a welding torch. Which diagram shows a molecule of acetylene? 33. The table shows the composition of natural gas. What is X? A ethanol B ethene C methane D propane 34. Which pair of compounds belong to the same homologous series? 35. The diagram shows the first four members of a homologous series. What is the difference in molecular formula between one member and the next in the series? A CH B CH 2 C CH 3 D CH 4 97

98 36. Which of the compounds shown are used as fuels? 37. The diagram shows the structure of an important product. This product is formed by..1.. of an..2.. Which words correctly complete gaps 1 and 2? 38. The diagram shows the structure of a small molecule. Which chain-like molecule is formed when these small molecules link together? 98

99 39. Ethanol can be formed by 1 fermentation, 2 reaction between steam and ethene. Which of these processes uses a catalyst? 40. An organic compound has the structure shown. From knowledge of the properties of alkanes and alkenes, which reactions would be predicted for this compound? 99

100 41. In the molecule shown, the two OH groups are numbered. Which of these OH groups react with aqueous sodium hydroxide? 42. When a suitable catalyst is used, ethene reacts with steam. What is the structure of the compound formed? 100

101 43. The diagram shows the separation of crude oil into fractions. What could X, Y and Z represent? 44. Which set of diagrams shows three substances that are all in the same homologous series? 101

102 45. The structures of three compounds are shown. What are X, Y and Z? 46. How many oxygen atoms and double bonds are there in one molecule of ethanoic acid? 47. Compounds R and S occur naturally. Which of the terms hydrocarbon and occurs in crude oil describe R and S? 102

103 48. The diagram shows an ethane molecule. Which compound has chemical properties similar to those of ethane? 49. The diagram shows part of a polymer. Which compound is used as the monomer? 103

104 13) ELECTROLYSIS 1. The diagram shows how aluminium is manufactured by electrolysis. What are the anode and cathode made of? 2. A student sets up the apparatus shown. The bulb does not light. After the student adds substance X to the water, the bulb lights. What is X? A calcium carbonate B carbon C copper(ii) sulphate D ethanol 104

105 3. The following electrolysis circuit is set up, using inert electrodes. At which electrode is a metal deposited? 4. The diagram shows a method used to electroplate a key with copper. Which aqueous solution is most suitable for the electrolyte? A copper(ii) sulphate B ethanol C sodium hydroxide D sulphuric acid 5. At which stage in the manufacture of magnesium from sea-water can electrolysis be used? 105

106 6. The following electrolysis circuit is set up, using inert electrodes P, Q, R and S. At which of the electrodes is a Group VII element produced? A P only B P and R C Q only D Q and S 7. In the circuit shown the bulb does not light. Which change would cause the bulb to light? A add more solid copper(ii) sulphate to the beaker B add water to dissolve the copper(ii) sulphate C replace the carbon electrodes with copper electrodes D reverse the connections to the electrodes 8. Metallic and non-metallic elements can both be extracted by electrolysis. Which element is produced at the negative electrode (cathode)? A bromine B chlorine C hydrogen D oxygen 106

107 9. The diagram shows an electrolysis experiment using metals X and Y as electrodes. One of the metals becomes coated with copper. Which metal becomes coated and which aqueous solution is used? 10. Which product is manufactured by electrolysis? A aluminium B copper(ii) sulphate C sodium chloride D steel 11. Which equation shows an oxidation reaction? 107

108 12. The diagram shows the electrolysis of molten lead(ii) bromide. What is seen at each electrode? 13. The diagram shows an electrolysis experiment to electroplate nickel with a different metal. Which nickel electrodes are plated with a metal? A 1 only B 1 and 3 only C 2 only D 2 and 4 only 108

109 14. The diagram shown is not complete. What should be shown at X when the solution has been electrolysed for some time? 15. The electrolysis of concentrated aqueous sodium chloride makes three products. Which products are shown at the correct electrodes? 109

110 16. The diagram shows that two gases are formed when concentrated hydrochloric acid is electrolysed between inert electrodes. Which line correctly describes the colours of the gases at the electrodes? 110

111 14) QUALITATIVE ANALYSIS 1. Which test method and gas are correctly linked? 2. A student heats a mixture of ammonium chloride and calcium hydroxide. She tests the gas given off with damp red litmus paper. What is the name of the gas and the final colour of the litmus paper? 3. The diagram shows the result of testing an aqueous solution Z. Which ion is present in solution Z? 111

112 A carbonate B chloride C nitrate D sulphate 4. An aqueous solution contains either aluminium sulphate or zinc sulphate. Which aqueous reagent can be used to confirm which salt is present? A ammonia B barium chloride C sodium hydroxide D sulphuric acid 5. Aqueous sodium hydroxide is added to two different solutions with the results shown. Which cation is present in X and in Y? 6. Aqueous ammonia is added to a solution of a metal sulphate. A green precipitate that is insoluble in excess of the aqueous ammonia forms. Which metal ion is present? 7. An ion X in solution is identified as shown. 112

113 8. What is used to test for the presence of water? A anhydrous copper(ii) sulphate B aqueous barium chloride C aqueous sodium hydroxide D Universal indicator paper 9. The presence of nitrates in soil can be shown by warming the soil with aqueous sodium hydroxide and aluminium foil. Which gas is given off? A ammonia B carbon dioxide C nitrogen D nitrogen dioxide 10. Bottles of sodium hydroxide, sodium chloride and sugar have lost their labels. Students test a sample from each bottle. Their results are shown in the table. What are the correct labels for each bottle? 11. Which aqueous ion causes a yellow precipitate to form when acidified aqueous lead(ii) nitrate is added to it? 113

114 A chloride B iodide C nitrate D sulphate 12. Which piece of equipment can be used to show that a gas is hydrogen? 13. The diagrams show three experiments. In which experiments is ammonia formed? A 1 only B 2 only C 3 only D 1, 2 and The diagrams show three experiments using dilute sulphuric acid. Three different powders are added to the acid. The mixtures are stirred. Which test-tubes then contain Cu2+(aq) ions? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and The diagram shows an experiment. 114

115 What is the name of the gas and the final colour of the litmus paper? 15) LABORATORY APPARATUS 1. A student mixes 25 cm3 samples of dilute hydrochloric acid with different volumes of aqueous sodium hydroxide. Each time, the student measures the change in temperature to test if the reaction is exothermic. Which piece of apparatus is not needed? 2. In an experiment, a student needs to measure out cm3 of a solution. Which piece of apparatus would measure this volume most accurately? A beaker B burette C measuring cylinder D pipette 115

116 3. The reaction between solution P and solution Q is exothermic. A student is told to test this statement by mixing equal volumes of the two solutions and measuring the temperature change. Which two pieces of apparatus should the student use? A balance and clock B balance and thermometer C pipette and clock D pipette and thermometer 4. Which piece of apparatus should be used for the accurate measurement of 30.0 cm 3 of a liquid? A a beaker B a burette C a conical flask D a measuring cylinder 5. A student mixes 25 cm 3 samples of dilute hydrochloric acid with different volumes of aqueous sodium hydroxide. Each time, the student measures the change in temperature. Which piece of apparatus is not needed? 6. Which piece of apparatus is essential to measure the speed of a reaction? A accurate balance B gas syringe C stopwatch D thermometer 116

117 PAPER 3 TOPIC PAGE 1) METALS 1 2) RATE OF REACTION 13 3) ORGANIC CHEMISTRY 19 4) ATOMIC STRUCTURE AND THE PERIODIC TABLE 35 5) MATTER 42 6) CHEMICAL CALCULATIONS 44 7) SULPUR AND ITS COMPOUNDS 47 8) NITROGEN AND ITS COMPOUNDS 52 9) STRUCTURE AND BONDING 56 10) THE ATMOSPHERE 60 11) ACIDS, BASES AND SALTS 64 12) ELECTROLYSIS 69 13) ENERGY

118 1) METALS 1. In 1886, the modern electrolytic process for the extraction of aluminium was discovered in the USA by C. Hall. (a) Before this discovery, the only method of extracting the metal was by displacement. (i) Name a metal that can displace aluminium from aluminium chloride.... [1] (ii) Write a word equation for this displacement reaction.... [1] (iii) Complete the equation for the reaction. (b) Aluminium is produced by the electrolysis of an electrolyte that contains aluminium oxide. (i) Write an ionic equation for the reduction of the aluminium ion at the cathode.... [2] (ii) Name the main ore of aluminium.... [1] (iii) Complete the following description of the electrolyte by filling the spaces. The electrolyte is a... mixture of aluminium oxide and... which is maintained at 900 C. [2] (iv) Explain why the gas given off at the anode is a mixture of oxygen and carbon dioxide [2] (c) One property of aluminium is that it resists corrosion because it is covered with a layer of its oxide. (i) Give one use of the metal that depends on this property.... [1] (ii) Give another use of the metal that depends on a different property. use... property... [2] 118

119 2. Manganese is a transition element. It has more than one valency and the metal and its compounds are catalysts. (a) (i) Predict three other properties of manganese that are typical of transition elements [3] (ii) Complete the electron distribution of manganese by inserting one number [1] (b) It has several oxides, three of which are shown below. Manganese(II) oxide, which is basic. Manganese(III) oxide, which is amphoteric. Manganese(IV) oxide, which is acidic. (i) Complete the word equation. manganese(ii) + hydrochloric acid oxide [2] (ii) Which, if any, of these oxides will react with sodium hydroxide?... [1] (c) Aqueous hydrogen peroxide decomposes to form water and oxygen. 2H 2 O 2 (aq) 2H 2 O(l) + O 2 (g) This reaction is catalysed by manganese (IV) oxide The following experiments were carried out to investigate the rate of this reaction. A 0.1 g sample of manganese (IV) oxide was added to 20 cm 3 of 0.2M hydrogen peroxide solution. The volume of oxygen produced was measured every minute. The results of this experiment are shown on the graph. 119

120 (i) How does the rate of reaction vary with time? Explain why the rate varies [3] (ii) The following experiment was carried out at the same temperature. 0.1 g of manganese (IV) oxide and 20 cm3 of 0.4M hydrogen peroxide Sketch the curve for this experiment on the same grid. [2] (iii) How would the shape of the graph differ if only half the mass of catalyst had been used in these experiments? [2] 3. For over 5000 years copper has been obtained by the reduction of its ores. More recently the metal has been purified by electrolysis. (a) Copper is used to make alloys. (i) Give two other uses of copper.... [2] (ii) Alloys have similar structures to pure metals. Give a labelled diagram that shows the structure of a typical alloy, such as brass. 120

121 (b) Copper is refined by the electrolysis of aqueous copper(ii) sulphate using copper electrodes. Describe the change that occurs at the electrodes. (i) cathode (pure copper) [1] (ii) anode (impure copper) [1] (iii) Write an ionic equation for the reaction at the cathode.... [1] (iv) If carbon electrodes are used, a colourless gas is given off at the anode and the electrolyte changes from a blue to a colourless solution. The colourless gas is.... The solution changes into.... [2] (c) Electrolysis and cells both involve chemical reactions and electricity. What is the essential difference between them? [2] (d) Copper is an unreactive metal. Its compounds are easily reduced to the metal or decomposed to simpler compounds. Complete the following equations. 4. No one knows where iron was first isolated. It appeared in China, the Middle East and in Africa. It was obtained by reducing iron ore with charcoal. (a) Complete the following equation. (b) In 1705 Abraham Darby showed that iron ore could be reduced using coke in a blast furnace. 121

122 (i) The temperature in the furnace rises to 2000 C. Write an equation for the exothermic reaction that causes this high temperature.... [1] (ii) In the furnace, the ore is reduced by carbon monoxide. Explain how this is formed [3] (c) The formation of slag removes an impurity in the ore. Write a word equation for the formation of the slag.... [2] (d) Stainless steel is an alloy of iron. It contains iron, other metals and about 0.5% of carbon. (i) State a use of stainless steel.... [1] (ii) Name a metal, other than iron, in stainless steel.... [1] (iii) The iron from the blast furnace is impure. It contains about 5% of carbon and other impurities, such as silicon and phosphorus. Describe how the percentage of carbon is reduced and the other impurities are removed [6] (e) One of the methods used to prevent iron or steel from rusting is to electroplate it with another metal, such as tin. Complete the following. 122

123 The anode is made of.... The cathode is made of.... The electrolyte is a solution of.... [3] 5. Zinc blende is the common ore of zinc. It is usually found mixed with an ore of lead and traces of silver. (a) (i) Describe how zinc blende is changed into zinc oxide [2] (ii) Write an equation for the reduction of zinc oxide by carbon.... [2] (iii) The boiling point of lead is 1740 C and that of zinc is 907 C. Explain why, when both oxides are reduced by heating with carbon at 1400 C, only lead remains in the furnace [2] (b) A major use of zinc is to make diecasting alloys. These contain about 4% of aluminium and they are stronger and less malleable than pure zinc. (i) Give one other large scale use of zinc.... [1] (ii) Describe the structure of a typical metal, such as zinc, and explain why it is malleable [3] (iii) Suggest why the introduction of a different metallic atom into the structure makes the alloy stronger than the pure metal [2] (c) A solution of an impure zinc ore contained zinc, lead and silver (I) ions. The addition of zinc dust will displace both lead and silver. (i) The ionic equation for the displacement of lead is as follows. Which change is reduction? Explain your answer

124 ... [2] (ii) Write an ionic equation for the reaction between zinc atoms and silver (I) ions.... [2] 6. (a) Copper has the structure of a typical metal. It has a lattice of positive ions and a sea of mobile electrons. The lattice can accommodate ions of a different metal. Give a different use of copper that depends on each of the following. (i) the ability of the ions in the lattice to move past each other [1] (ii) the presence of mobile electrons [1] (iii) the ability to accommodate ions of a different metal in the lattice [1] (b) Aqueous copper (II) sulphate solution can be electrolysed using carbon electrodes. The ions present in the solution are as follows. (i) Write an ionic equation for the reaction at the negative electrode (cathode). [1] (ii) A colourless gas was given off at the positive electrode (anode) and the solution changes from blue to colourless. Explain these observations. [2] (c) Aqueous copper(ii) sulphate can be electrolysed using copper electrodes. The reaction at the negative electrode is the same but the positive electrode becomes smaller and the solution remains blue. (i) Write a word equation for the reaction at the positive electrode. [1] (ii) Explain why the colour of the solution does not change. [2] (iii) What is the large scale use of this electrolysis? [1] 7. In the following list of ionic equations, the metals are in order of reactivity. (a) (i) In the space at the top of the series, write an ionic equation that includes a more reactive metal. [1] 124

125 (ii) Define oxidation in terms of electron transfer. [1] (iii) Explain why the positive ions are likely to be oxidising agents. [1] (iv) Which positive ion(s) can oxidise mercury metal (Hg)? [1] 8. The position of aluminium in the reactivity series of metals is shown below. (a) Aluminium is extracted by the electrolysis of its molten oxide. (i) Name the main ore of aluminium. [1] (ii) Why does the molten electrolyte contain cryolite? [1] (iii) Oxygen is produced at the positive electrode (anode). Name another gas which is given off at this electrode. [1] (b) Aluminium reacts very slowly with aqueous copper(ii) sulphate. (i) Which of the two metals has the greater tendency to form ions? [1] (ii) Describe what you would see when this reaction occurs. [1] (iii) Explain why aluminium reacts so slowly. [1] 125

126 (c) Complete the following table by writing reaction or no reaction in the spaces provided. (d) Predict the equations for the decomposition of the following aluminium compounds. 9. The major ore of zinc is zinc blende, ZnS. (i) Describe how zinc is extracted from zinc blende. [2] (ii) Give a use of zinc. [1] 10. (i) Write a word equation for the reaction of zinc and water and state the reaction conditions. word equation [1] conditions [2] (ii) Write an equation for the reaction of strontium with water and give the reaction condition. equation [2] condition [1] 126

127 11.(a) Iron is extracted in a blast furnace. The list below gives some of the substances used or formed in the extraction. (i) Which substance is a mineral containing largely calcium carbonate? [1] (ii) Which substance is formed when impurities in the ore react with calcium oxide? [1] (iii) Which substance is also called hematite? [1] (b) State two functions of the coke used in the blast furnace. [2] (e) Most of the iron is converted into mild steel or stainless steel. Give one use for each. mild steel stainless steel [2] 12. Some reactions of metals W, X, Y and Z are given below. (a) Arrange these metals in order of reactivity. most reactive least reactive [2] (b) Which of these metals could be (i) magnesium, [1] (ii) copper? [1] (c) The equation for the reaction of X with cold water is given below. 127

128 (i) Describe the test you would use to show that the gas evolved is hydrogen. [1] (ii) How could you show that the water contained a compound of the type XOH? [2] (iii) In which group of the Periodic Table does metal X belong? [1] (iv) The ore of X is its chloride. Suggest how metal X could be extracted from its chloride. [2] 13. Iron is a transition element. 14. An ore of copper is the mineral, chalcopyrite. This is a mixed sulphide of iron and copper. (a) Analysis of a sample of this ore shows that g of the ore contained 4.80 g of copper, 4.20 g of iron and the rest sulphur. Complete the table and calculate the empirical formula of chalcopyrite. 128

129 The empirical formula is [1] (b) Impure copper is extracted from the ore. This copper is refined by electrolysis. (i) Name; the material used for the positive electrode (anode), the material used for the negative electrode (cathode), a suitable electrolyte. [3] (ii) Write an ionic equation for the reaction at the negative electrode. [1] (iii) One use of this pure copper is electrical conductors, another is to make alloys. Name the metal that is alloyed with copper to make brass. [1] (c) Two of the elements in chalcopyrite are the metal, copper, and the non-metal, sulphur. These have different properties. Copper is an excellent conductor of electricity and is malleable. Sulphur is a poor conductor and is not malleable, it is brittle. Explain, in terms of their structures, why this is so. difference in electrical conductivity [2] difference in malleability [2] 15. (a) Zinc is made by reducing zinc oxide. In 1695 Homberg obtained zinc from calamine, zinc carbonate. At present zinc is extracted from the ore, zinc blende. (i) Suggest a way of changing calamine into zinc oxide.... [1] (ii) Describe how zinc is extracted from zinc blende

130 [3] (b) Zinc oxide is used to make aqueous zinc chloride. This can be used to preserve wood. Describe how this solution could be made [3] (c) Zinc is used to make alloys. (i) Name an alloy that contains zinc.... [1] (ii) What is the other metal in this alloy?... [1] (d) Another use of zinc is galvanising. When the zinc layer is broken, the steel is exposed. Explain why the exposed steel does not rust [3] 2) RATE OF REACTION 1.The graph shows how the rate of the exothermic reaction between aluminium and hydrochloric acid varies with time. 130

131 (i) Suggest a reason why the reaction goes slowly at first.... [1] (ii) Suggest two reasons for the increase in rate [2] 2. Some of the factors that can determine the rate of a reaction are concentration, temperature and light intensity. (a) A small piece of calcium carbonate was added to an excess of hydrochloric acid. The time taken for the carbonate to react completely was measured. The experiment was repeated at the same temperature, using pieces of calcium carbonate of the same size but with acid of a different concentration. In all the experiments an excess of acid was used. (i) Complete the table (assume the rate is proportional to both the acid concentration and the number of pieces of calcium carbonate). [3] (ii) Explain why the reaction rate would increase if the temperature was increased [2] 131

132 (iii) Explain why the rate of this reaction increases if the piece of carbonate is crushed to a powder.... [1] (iv) Fine powders mixed with air can explode violently. Name an industrial process where there is a risk of this type of explosion [1] (b) Sodium chlorate (I) decomposes to form oxygen and sodium chloride. This is an example of a photochemical reaction. The rate of reaction depends on the intensity of the light. (i) Describe how the rate of this reaction could be measured [2] (ii) How could you show that this reaction is photochemical? [1] (c) Photosynthesis is another example of a photochemical reaction. Glucose and more complex carbohydrates are made from carbon dioxide and water. (i) Complete the equation. (ii) Glucose can be represented as Draw the structure of a more complex carbohydrate that can be formed from glucose by condensation polymerisation. 3. The rate of this reaction can be measured using the following apparatus. 132

133 The results of this experiment are shown on the graph below. (i) How does the rate of this reaction vary with time? [1] (ii) Why does the rate vary? [2] (iii) The reaction is catalysed by copper powder. Sketch the graph for the catalysed reaction on the same grid. [2] (iv) Why is copper powder more effective as a catalyst than a single piece of copper? [1] 4. Reversible reactions can come to equilibrium. They have both a forward and a backward reaction. 133

134 (a) When water is added to an acidic solution of bismuth (III) chloride, a white precipitate forms and the mixture slowly goes cloudy. (i) Explain why the rate of the forward reaction decreases with time. [2] (ii) Why does the rate of the backward reaction increase with time? [1] (iii) After some time why does the appearance of the mixture remain unchanged? [2] (iv) When a few drops of concentrated hydrochloric acid are added to the cloudy mixture, it changes to a colourless solution. Suggest an explanation. [2] (b) Both of the following reactions are reversible. (i) Suggest a reason why an increase in pressure does not affect the position of equilibrium for reaction 1. [1] (ii) What effect would an increase in pressure have on the position of equilibrium for reaction 2? Give a reason for your answer. [2] 5. The rate of a reaction depends on concentration of reactants, temperature and possibly a catalyst or light. (a) A piece of magnesium ribbon was added to 100 cm3 of 1.0 mol/dm3 hydrochloric acid. The hydrogen evolved was collected in a gas syringe and its volume measured every 30 seconds. 134

135 In all the experiments mentioned in this question, the acid was in excess. The results were plotted to give a graph. (i) The experiment was repeated. Two pieces of magnesium ribbon were added to 100 cm 3 of 1.0 mol/dm 3 hydrochloric acid. Sketch this graph on the same grid and label it X. [2] 135

136 (ii) The experiment was repeated using one piece of magnesium ribbon and 100 cm 3 of 1.0 mol/dm 3 ethanoic acid. Describe how the shape of this graph would differ from the one given on the grid. [2] (b) Reaction rate increases when concentration or temperature is increased. Using the idea of reacting particles, explain why; increasing concentration increases reaction rate, [2] increasing temperature increases reaction rate. [2] (c) The rate of a photochemical reaction is affected by light. A reaction, in plants, between carbon dioxide and water is photochemical. (i) Name the two products of this reaction. [2] (ii) This reaction will only occur in the presence of light and another chemical. Name this chemical.[1] 3) ORGANIC CHEMISTRY 1. A major food retailer in the UK is going to distribute sandwiches using hydrogen-powered vehicles. (a) A sandwich contains three of the main constituents of food. 136

137 These constituents of food can all be hydrolysed by boiling with acid or alkali. (i) Complete the table. [5] (ii) What type of synthetic polymer contains the same linkage as proteins,... fats?... [2] (iii) Fats can be unsaturated or saturated. A small amount of a fat was dissolved in an organic solvent. Describe how you could find out if this fat was saturated or unsaturated. reagent... result if saturated... result if unsaturated [3] (b) One of the reasons for using hydrogen as a fuel is to reduce air pollution. Petroleum powered vehicles are a major cause of air pollution. This pollution can be decreased by reactions of the type shown below. 2CO + 2NO N 2 + 2CO 2 (i) Where in a vehicle does this type of reaction occur?... [1] 137

138 (ii) Explain how carbon monoxide is formed in the engine [2] (iii) Give a reason why the hydrogen-powered vehicle produces less pollution.... [1] (c) Outline how hydrogen is manufactured from water [2] 2. Alkenes are unsaturated hydrocarbons. They show structural isomerism. Alkenes take part in addition reactions and form polymers. (a) Structural isomers have the same molecular formula but different structural formulae. Give an example of structural isomerism. molecular formula... two structural formulae [3] (b) Ethene reacts with each of the following. Give the name and structural formula of each product. (i) steam name of product... structure of product (ii) hydrogen [2] name of product... structure of product [2] (c) Alkenes polymerise by addition. (i) Explain the term polymerise [2] 138

139 (ii) What is the difference between addition polymerisation and condensation polymerisation? [2] (iii) Poly (dichloroethene) is used extensively to package food. Draw its structure. The structural formula of dichloroethene is drawn below. (d) Steel may be coated with another metal, eg zinc or chromium, or with a polymer, eg (chloroethene), to prevent rusting. [2] poly (i) Suggest a property of poly (chloroethene) that makes it suitable for this purpose.... [1] (ii) Explain why the steel will rust when the protective coating of chromium or polymer is broken.... [1] (iii) When the protective layer of zinc is broken, the steel still does not rust. Suggest an explanation [2] 3. Alkenes are unsaturated hydrocarbons. They undergo addition reactions. (a) Two of the methods of making alkenes are cracking and the thermal decomposition of chloroalkanes. (i) Complete an equation for the cracking of the alkane, decane. (ii) Propene can be made by the thermal decomposition of chloropropane. Describe how chloropropane can be made from propane. reagents propane and... conditions... [4] (b) The following alkenes are isomers. 139

140 (i) Explain why they are isomers (ii) Give the name and structural formula of another hydrocarbon that is isomeric with the above. name... structural formula (c) Give the name of the product when but-1-ene reacts with each of the following. [4] steam... hydrogen... bromine... [3] (d) Alkenes can polymerise. (i) Deduce the name and structural formula of the monomer from the structure of the polymer. name of monomer... structural formula (ii) Draw the structure of the polymer formed from the following monomer. [3] 140

141 [2] (iii) Describe the pollution problems caused by the disposal of polymers in landfill sites and by burning. landfill sites [2] burning [1] 4. Esters occur naturally in plants and animals. They are manufactured from petroleum. Ethyl ethanoate and butyl ethanoate are industrially important as solvents. (a) (i) Explain the term solvent.... [1] (ii) Give the formula of ethyl ethanoate. [1] (iii) Ethyl ethanoate can be made from ethanol and ethanoic acid. Describe how these chemicals can be made. ethanol from ethene [2] ethanoic acid from ethanol [2] (iv) Name two chemicals from which butyl ethanoate can be made.... [1] (b) The following equation represents the alkaline hydrolysis of a naturally occurring ester. (i) Which substance in the equation is an alcohol? Underline the substance in the equation above. [1] (ii) What is the major use for compounds of the type C 17 H 35 COONa? 141

142 ... [1] (c) A polymer has the structure shown below. (i) What type of polymer is this?... [1] (ii) Complete the following to give the structures of the two monomers from which the above polymer could be made. (d) Esters are frequently used as solvents in chromatography. A natural macromolecule was hydrolysed to give a mixture of amino acids. These could be identified by chromatography. (i) What type of macromolecule was hydrolysed?... [1] (ii) What type of linkage was broken by hydrolysis?... [1] (iii) Explain why the chromatogram must be sprayed with a locating agent before the amino acids can be identified [1] (iv) Explain how it is possible to identify the amino acids from the chromatogram [2] [2] 5. In 2002, Swedish scientists found high levels of acrylamide in starchy foods that had been cooked above 120 o C. Acrylamide, which is thought to be a risk to human health, has the following structure. 142

143 It readily polymerises to polyacrylamide. Draw the structure of this polymer. [2] 6. The simplest alcohol is methanol. (a) It is manufactured by the following reversible reaction. (i) Reversible reactions can come to equilibrium. Explain the term equilibrium. [1] (ii) At 400 o C, the percentage of methanol in the equilibrium mixture is lower than at 300 o C. Suggest an explanation. [2] (iii) Suggest two advantages of using high pressure for this reaction. Give a reason for each advantage. 143

144 7. Polymers are extensively used in food packaging. Poly(dichloroethene) is used because gases can only diffuse through it very slowly. Polyesters have a high thermal stability and food can be cooked in a polyester bag. (a) (i) The structure of poly(dichloroethene) is given below. Draw the structural formula of the monomer. (ii) Explain why oxygen can diffuse faster through the polymer bag than carbon dioxide can. [2] [2] (b) (i) A polyester can be formed from the monomers HO-CH 2 CH 2 -OH and HOOC-C 6 H 4 -COOH. Draw the structure of this polyester. [2] (ii) Name a naturally occurring class of compounds that contains the ester linkage. [1] 144

145 (iii) Suggest what is meant by the term thermal stability. [1] (c) (i) Describe two environmental problems caused by the disposal of plastic (polymer) waste. [2] (ii) The best way of disposing of plastic waste is recycling to form new plastics. What is another advantage of recycling plastics made from petroleum? [1] 8. The alkenes are a homologous series of unsaturated hydrocarbons. (a) The table below gives the names, formulae and boiling points of the first members of the series. (i) Complete the table by giving the formula of hexene and by predicting its boiling point. [2] (ii) Deduce the formula of the alkene which has a relative molecular mass of 168. Show your working. [2] (b) Describe a test that will distinguish between the two isomers, but-2-ene and cyclobutane. test result with but-2-ene result with cyclobutane [3] (c) Alkenes undergo addition reactions. (i) What class of organic compound is formed when an alkene reacts with water? [1] 145

146 (ii) Predict the structural formula of the compound formed when hydrogen chloride reacts with but-2-ene. [1] (iii) Draw the structure of the polymer formed from but-2-ene. [2] 9. Enzymes are biological catalysts. They are used both in research laboratories and in industry. (a) Enzymes called proteases can hydrolyse proteins to amino acids. The amino acids can be separated and identified by chromatography. The diagram below shows a typical chromatogram. Some Rf values for amino acids are: glutamic acid = 0.4 glycine = 0.5 alanine = 0.7 leucine = 0.9 Identify the two amino acids on the chromatogram. A is.b is.. [2] 146

147 (ii) Explain why the chromatogram must be exposed to a locating agent before Rf values can be measured. [1] (iii) Measuring Rf values is one way of identifying amino acids on a chromatogram. Suggest another. [1] (iv) The synthetic polymer, nylon, has the same linkage as proteins. Draw the structural formula of nylon. (b) Enzymes called carbohydrases can hydrolyse complex carbohydrates to simple sugars [3] (c) Fermentation can be carried out in the apparatus drawn below. After a few days the reaction stops. It has produced a 12% aqueous solution of ethanol. [2] (i) Complete the equation. [2] (ii) Zymase catalyses the anaerobic respiration of glucose. Define the term respiration. [2] 147

148 (iii) Suggest a reason why the reaction stops after a few days. [1] (iv) Why is it essential that there is no oxygen in the flask? [1] (v) What technique is used to concentrate the aqueous ethanol? [1] 10. The alcohols form a homologous series. The first member is methanol and the fourth is butanol. (a) (i) Give two general characteristics of a homologous series. [2] (ii) Calculate the mass of one mole of the C 8 alcohol. [2] (b) Give the name and structural formula of the third member of this series. name [1] structural formula [1] (c) The structural formula of the fifth member, pentan-1-ol, is drawn below. (i) Draw the structural formula of an isomer of this alcohol. [1] (ii) Predict the names of the product(s) formed when pentan-1-ol reacts with an excess of oxygen, and.. [1] is dehydrated to form an alkene, [1] is oxidised by acidified potassium dichromate (VI). [1] 11. The fractional distillation of crude oil usually produces large quantities of the heavier fractions. The market demand is for the lighter fractions and for the more reactive alkenes. The heavier fractions are cracked to form smaller alkanes and alkenes as in the following example. 148

149 (a) (i) Write a different equation for the cracking of octane. (ii) The cracking of octane can produce isomers with the molecular formula C 4 H 8. Draw the structural formulae of two of these isomers. [2] (b) (i) Give the essential condition for the reaction between chlorine and butane. [1] (ii) What type of reaction is this? [1] (iii) This reaction produces a mixture of products. Give the names of two products that contain four carbon atoms per molecule..and.. [2] c) Alkenes are more reactive than alkanes and are used to make a range of organic chemicals. Propene, CH 3 CH=CH 2, is made by cracking. Give the structural formula of the addition product when propene reacts with the following. (i) water (ii) bromine [1] 12. The three types of food are carbohydrates, proteins and fats. (a) Aqueous starch is hydrolysed to maltose by the enzyme amylase. The formula of maltose is: Starch is hydrolysed by dilute sulphuric acid to glucose. (i) What is an enzyme? [1] (ii) Draw the structure of starch. [1] 149

150 (iii) Name the technique that would show that the products of these two hydrolyses are different. [1] (b) Proteins have the same linkage as nylon but there is more than one monomer in the macromolecule. (i) Draw the structure of a protein. [2] (ii) What class of compound is formed by the hydrolysis of proteins? [1] (c) Fats are esters. Some fats are saturated, others are unsaturated. (i) Write the word equation for the preparation of the ester, propyl ethanoate. [2] (ii) Deduce the structural formula of this ester showing each individual bond. [2] (iii) How could you distinguish between these two fats? Fat 1 has the formula Fat 2 has the formula test result with fat 1 result with fat 2 [3] (iv) Both of these fats are hydrolysed by boiling with aqueous sodium hydroxide. What type of compounds are formed?.and. [2] 150

151 13. Pure nickel is used to catalyse the reduction of unsaturated oils to saturated fats. (i) What is meant by the terms saturated and unsaturated? [2] (ii) Name the functional group in fats.... [1] (iii) How can a soap be made from a fat?... [2] 14. Propane is an alkane. It has the structural formula: (a) The equation for the complete combustion of propane is given below. Insert the two missing volumes. (b) Propane reacts with chlorine to form two chloropropanes with the formula C 3 H 7 Cl. (i) Write an equation for this reaction.... [1] (ii) What type of reaction is this?... [1] (c) The two chloropropanes react with sodium hydroxide to form different alcohols. (i) These alcohols are isomers. Using the propanols as an example explain the term isomer [3] (ii) Fractional distillation can separate the two propanols. Suggest a reason why this method is effective.... [1] (iii) Oxygen can oxidise propanol to propanoic acid. Name another reagent that will bring about this reaction.... [1] 151

152 (iv) Propanol and propanoic acid react to form an ester. Give the name and structural formula of an ester. name... structural formula (d) Propene can be made by heating propane and sulphur. (i) Outline another method of making alkenes from alkanes [2] (ii) Outline how propanol could be made from propene [2] [3] 1. Bromine is one of the halogens in Group VII. 4) ATOMIC STRUCTURE AND THE PERIODIC TABLE (a) (i) Predict which halogen has the lightest colour.... [1] 152

153 (ii) Predict which halogens are solids at room temperature.... [1] (b) Bromine is obtained from the bromide ions in sea water. Sea water is concentrated by evaporation. Chlorine gas is bubbled through the solution. Chlorine oxidises the bromide ion to bromine. (i) Complete the following equation. (ii) Explain using the idea of electron transfer why the bromide ion is oxidised by chlorine. The bromide ion is oxidised because Chlorine is the oxidising agent because [2] (iii) Name a reagent that can be oxidised by bromine molecules.... [1] (c) Bromine reacts with phosphorus to form phosphorus tribromide. Draw a diagram showing the arrangement of the valency electrons in one molecule of this covalent compound. The electron distribution of bromine is: (ii) Explain using the idea of electron transfer why the bromide ion is oxidised by chlorine. The bromide ion is oxidised because Chlorine is the oxidising agent because [2] (iii) Name a reagent that can be oxidised by bromine molecules.... [1] (c) Bromine reacts with phosphorus to form phosphorus tribromide. Draw a diagram showing the arrangement of the valency electrons in one molecule of this covalent compound. The electron distribution of bromine is: Use x to represent an electron from phosphorus. Use o to represent an electron from bromine. [3] (d) Phosphorus tribromide reacts with water to form two acids. (i) Balance the equation for this reaction. (ii) Describe by giving essential details how you could show that phosphorous acid, H 3 PO 3, is a weaker acid than hydrogen bromide. 153

154 [2] (e) Hydrogen bromide is an acid. When it is dissolved in water the following reaction occurs. (i) Name the particle lost by the hydrogen bromide molecule.... [1] (ii) What type of reagent is the water molecule in this reaction?... [1] 2. The elements in Period 3 and some of their common oxidation states are shown below. Element Na Mg Al Si P S Cl Ar Oxidation State (a) (i) Why do the oxidation states increase from sodium to silicon?... [1] (ii) After Group (IV) the oxidation states are negative and decrease across the period. Explain why [2] (b) The following compounds contain two elements. Predict their formulae. aluminium sulphide... silicon phosphide... [2] (c) Choose a different element from Period 3 that matches each description. (i) It has a similar structure to diamond.... [1] (ii) It reacts violently with cold water to form a solution ph = [1] (iii) It has a gaseous oxide of the type XO 2, which is acidic.... [1] (d) The only oxidation state of argon is zero. Why it is used to fill light bulbs? [1] (e) Draw a diagram that shows the arrangement of the valency electrons in the ionic compound sodium phosphide. Use o to represent an electron from sodium. Use x to represent an electron from phosphorus. [3] (f) Sodium reacts with sulphur to form sodium sulphide. 2Na + S Na 2 S 154

155 An 11.5 g sample of sodium is reacted with 10 g of sulphur. All of the sodium reacted but there was an excess of sulphur. Calculate the mass of sulphur left unreacted. (i) Number of moles of sodium atoms reacted =... [2 moles of Na react with 1 mole of S] (ii) Number of moles of sulphur atoms that reacted =... (iii) Mass of sulphur reacted =...g (iv) Mass of sulphur left unreacted =...g [4] 3. Calcium and other minerals are essential for healthy teeth and bones. Tablets can be taken to provide these minerals. (a) Boron is a non-metal with a macromolecular structure. (i) What is the valency of boron?... [1] (ii) Predict two physical properties of boron [2] (iii) Name another element and a compound that have macromolecular structures. element.. compound [2] (iv) Sketch the structure of one of the above macromolecular substances. 155

156 (b) Describe the reactions, if any, of zinc and copper (II) ions with an excess of aqueous sodium hydroxide. (i) zinc ions addition of aqueous sodium hydroxide excess sodium hydroxide (ii) copper(ii) ions addition of aqueous sodium hydroxide excess sodium hydroxide [4] (c) Each tablet contains the same number of moles of CaCO 3 and MgCO 3. One tablet reacted with excess hydrochloric acid to produce 0.24 dm 3 of carbon dioxide at r.t.p. (i) Calculate how many moles of CaCO3 there are in one tablet. number of moles CO 2 =... number of moles of CaCO 3 and MgCO 3 =... number of moles of CaCO 3 =... [3] (ii) Calculate the volume of hydrochloric acid, 1.0 mol /dm 3, needed to react with one tablet. number of moles of CaCO 3 and MgCO 3 in one tablet =... Use your answer to (c)(i). number of moles of HCl needed to react with one tablet =... volume of hydrochloric acid, 1.0 mol /dm 3, needed to react with one tablet =... [2] 4. The first three elements in Period 6 of the Periodic Table of the Elements are caesium, barium and lanthanum. (a) How many more protons, electrons and neutrons are there in one atom of lanthanum than in one atom of caesium? Use your copy of the Periodic Table of the Elements to help you. number of protons... number of electrons... number of neutrons... [3] (b) All three metals can be obtained by the electrolysis of a molten halide. The electrolysis of the aqueous halides does not produce the metal. 156

157 (i) Complete the equation for the reduction of lanthanum ions at the negative electrode (cathode). (ii) Name the three products formed by the electrolysis of aqueous caesium bromide [4] (c) All three metals react with cold water. Complete the word equation for these reactions. Metal + water.. + [2] (d) Barium chloride is an ionic compound. Draw a diagram that shows the formula of the compound, the charges on the ions and gives the arrangement of the valency electrons around the negative ion. The electron distribution of a barium atom is Use x to represent an electron from a barium atom. Use o to represent an electron from a chlorine atom. [2] (e) Describe, by means of a simple diagram, the lattice structure of an ionic compound, such as caesium chloride. [2] (f) The reactions of these metals with oxygen are exothermic. (i) Give an example of bond forming in this reaction.... (ii) Explain using the idea of bond breaking and forming why this reaction is exothermic [3] 5. An organic compound decomposes to form nitrogen. C 6 H 5 N 2 Cl(aq) C 6 H 5 Cl(l) + N 2 (g) (a) Explain the state symbols. aq l g [2] 157

158 (b) Draw a diagram to show the arrangement of the valency electrons in one molecule of nitrogen. [2] 6. Strontium and sulphur chlorides both have a formula of the type XCl 2 but they have different properties. (a) The formulae of the chlorides are similar because both elements have a valency of 2. Explain why Group II and Group VI elements both have a valency of 2. (b) Draw a diagram showing the arrangement of the valency electrons in one covalent molecule of sulphur chloride. Use x to represent an electron from a sulphur atom. Use o to represent an electron from a chlorine atom. [3] (c) Explain the difference in electrical conductivity between the following: (i) solid and liquid strontium chloride [1] (ii) liquid strontium chloride and liquid sulphur chloride [1] 7. Strontium and zinc are both metals with a valency of 2. Strontium is more reactive than zinc. Its chemistry is similar to that of calcium. (a) (i) Complete the following table that shows the number of protons, electrons and neutrons in each particle. 158

159 (ii) Explain why 88 Sr and 90 Sr are isotopes. [1] (iii) Complete the electron distribution of an atom of strontium. 8. (i) In which Period in the Periodic Table is iron to be found? [1] (ii) Use the Periodic Table to work out the number of protons and the number of neutrons in one atom of iron. 9. Choose a gas from the following list to answer the questions below. Each gas may be used once, more than once or not at all. Which gas (i) is a noble gas, (ii) is an acidic oxide, (iii) can be polymerised, (iv) is the active component of air, (v) is used in the treatment of water, (vi) is a product of respiration? [6] 5) MATTER 1. (a) The Kinetic Theory explains the properties of solids, liquids and gases in terms of the movement of particles. Liquids and gases both take up the shape of the container but a gas always fills the container. Explain this, using the ideas of the Kinetic Theory. 159

160 [4] (b) The following apparatus can be used to measure the rate of diffusion of a gas. (i) What measurements would need to be taken to calculate the rate of diffusion of a gas?... [2] (ii) Which gas, carbon dioxide or sulphur dioxide, would diffuse faster? Explain your choice [3] 2. Ethanoic acid is a colourless liquid at room temperature. It has the typical acid properties and forms compounds called ethanoates. (a) A pure sample of ethanoic acid is slowly heated from 0 o C to 150 o C and its temperature is measured every minute. The results are represented on the graph below. 160

161 i) Name the change that occurs in the region D to E. [1] (ii) What would be the difference in the region B to C if an impure sample had been used? [1] (iii) Sketch on the graph how the line would continue if the acid was heated to a higher temperature. [1] (iv) Complete the following table that compares the separation and movement of the molecules in regions C to D with those in E to F. 6) CHEMICAL CALCULATIONS 1. (a) A 20 cm 3 sample of butyne, C 4 H 6, is burnt in 150 cm 3 of oxygen. This is an excess of oxygen. 161

162 (i) What volume of oxygen reacts?... [1] (ii) What volume of carbon dioxide is produced?... [1] (iii) What is the total volume of gases left at the end of the reaction?... [1] (b) Calculate the mass of water formed when 9.0 g of butyne is burnt. The mass of one mole of butyne is 54 g. from the above equation, 1 mole of butyne forms 3 moles of water number of moles of butyne reacted... number of moles of water formed... mass of water formed... g [3] 2. Iron (III) sulphate decomposes when heated. Calculate the mass of iron (III) oxide formed and the volume of sulphur trioxide produced when 10.0 g of iron (III) sulphate was heated. Mass of one mole of Fe 2 (SO 4 ) 3 is 400 g. [3] 3. Gypsum is hydrated calcium sulphate, CaSO4.xH2O. It contains 20.9% water by mass. Calculate x. (Mr: CaSO 4 =136; H 2 O = 18) 79.1 g of CaSO 4 =.. moles 20.9 g of H 2 O =.. moles x = [3] 4. (a) The following method is used to make crystals of hydrated nickel sulphate. An excess of nickel carbonate, 12.0 g, was added to 40 cm 3 of sulphuric acid, 2.0 mol/dm 3. The unreacted nickel carbonate was filtered off and the filtrate evaporated to obtain the crystals. Mass of one mole of NiSO 4.7H 2 O = 281 g 162

163 Mass of one mole of NiCO 3 = 119 g (i) Calculate the mass of unreacted nickel carbonate. Number of moles of H 2 SO 4 in 40 cm 3 of 2.0 mol/dm 3 acid = 0.08 Number of moles of NiCO 3 reacted = Mass of nickel carbonate reacted =. g Mass of unreacted nickel carbonate =.g [3] (ii) The experiment produced 10.4 g of hydrated nickel sulphate. Calculate the percentage yield. The maximum number of moles of NiSO 4.7H 2 O that could be formed =. The maximum mass of NiSO 4.7H 2 O that could be formed = g The percentage yield =. % [3] 5. Propene reacts with hydrogen iodide to form 2 - iodopropane. 6. When calcium carbonate is heated strongly, it decomposes. (i) Calculate the relative formula mass of: CaCO3 CaO [2] 163

164 (ii) 7.00 kg of calcium oxide was formed. What mass of calcium carbonate was heated? [3] 7. Potassium chlorate, which has a formula of the type, KClOn, decomposes to form oxygen g of the chlorate produced 1.49 g of potassium chloride and 0.72 dm 3 of oxygen at r.t.p. Find the value of n. 1. (a) Sulphuric acid is made by the Contact Process. 7) SULPUR AND ITS COMPOUNDS forward reaction is exothermic (i) What are the reaction conditions for the Contact Process? [3] 164

165 (ii) Would the yield of sulphur trioxide increase, decrease or stay the same when the temperature is increased? Explain your answer [2] (iii) Describe how sulphur trioxide is changed into concentrated sulphuric acid [2] (b) There are three ways of making salts from sulphuric acid. titration using a burette and indicator precipitation by mixing the solutions and filtering neutralisation of sulphuric acid using an excess of an insoluble base Complete the following table of salt preparations. (c) The results of an investigation into the action of heat on copper (II) sulphate-5-water, a blue crystalline solid, are given below. The formula is CuSO 4.5H 2 O and the mass of one mole is 250 g A 5.0 g sample of the blue crystals is heated to form 3.2 g of a white powder. With further heating this decomposes into a black powder and sulphur trioxide. (i) Name the white powder.... [1] (ii) What is observed when water is added to the white powder?... [1] (iii) Name the black powder.... [1] (iv) Calculate the mass of the black powder. Show your working [3] 2. Sulphur dioxide, SO2, and sulphur trioxide, SO3, are the two oxides of sulphur. [4] 165

166 (a) Sulphur dioxide can kill bacteria and has bleaching properties. Give a use of sulphur dioxide that depends on each of these properties. (i) ability to kill bacteria... [1] (ii) bleaching properties... [1] (b) Sulphur trioxide can be made from sulphur dioxide. (i) Why is this reaction important industrially?... [1] (ii) Complete the word equation. sulphur dioxide +. sulphur trioxide [1] (iii) What are the conditions for this reaction? [2] (c) Sulphur dioxide is easily oxidised in the presence of water. (i) What colour change would be observed when an excess of aqueous sulphur dioxide is added to an acidic solution of potassium manganate (VII)?... [2] (ii) To aqueous sulphur dioxide, acidified barium chloride solution is added. The mixture remains clear. When bromine is added, a thick white precipitate forms. What is the white precipitate? Explain why it forms [3] (d) Sulphur dioxide reacts with chlorine in an addition reaction to form sulphuryl chloride. 8.0 g of sulphur dioxide was mixed with 14.2 g of chlorine. The mass of one mole of SO 2 Cl 2 is 135 g. Calculate the mass of sulphuryl chloride formed by this mixture. Calculate the number of moles of SO 2 in the mixture = Calculate the number of moles of Cl 2 in the mixture = Which reagent was not in excess?. How many moles of SO 2 Cl 2 were formed =. Calculate the mass of sulphuryl chloride formed =. g [5] 166

167 3. Sulphur is used to make sulphuric acid. In the UK, the annual production of the acid is about 2.5 million tonnes. (a) The reactions in the manufacture of sulphuric acid by the Contact Process are shown below. (i) Give a large scale source of the element sulphur. [1] (ii) State another use of sulphur dioxide. [1] (iii) How is sulphur changed into sulphur dioxide? [1] (iv) Name the catalyst used in reaction 2. [1] (v) Reaction 2 is exothermic. Why is a catalyst, rather than a higher temperature, used to increase the rate of this reversible reaction? [2] (vi) Write a word equation for reaction 3. [1] (vii) Write a symbol equation for reaction 4. [1] (b) About one third of this production of acid is used to make nitrogen and phosphorus containing fertilisers. (i) Name the third element that is essential for plant growth and is present in most fertilisers. [1] (ii) Name a nitrogen-containing fertiliser that is manufactured from sulphuric acid. [1] (iii) Rock phosphate (calcium phosphate) is obtained by mining. It reacts with concentrated sulphuric acid to form the fertiliser, superphosphate. Predict the formula of each of these phosphates. 167

168 (iv) The ionic equation for the reaction between the phosphate ion and sulphuric acid is shown below. Explain why the phosphate ion is described as acting as a base in this reaction. [2] 4. Sulphuric acid is manufactured by the Contact Process. Sulphur dioxide is oxidised to sulphur trioxide by oxygen. (i) Name the catalyst used in this reaction. [1] (ii) What temperature is used for this reaction? [1] (iii) Describe how sulphur trioxide is changed into sulphuric acid. [2] 5. Sulphuric acid is made by the Contact process in the following sequence of reactions. (a) (i) How is sulphur dioxide made from sulphur? [1] (ii) Sulphur dioxide has other uses. Why is it used in the manufacture of paper? [1] (iii) How does it preserve food? [1] (b) The equation for a stage of the Contact process is The percentage of sulphur trioxide in the equilibrium mixture varies with temperature. 168

169 (i) How does the percentage of sulphur trioxide in the equilibrium mixture vary as the temperature increases? Circle the correct answer. (iii) Explain, mentioning both rate and percentage yield, why the temperature used in the Contact process is 450 C. [2] (iv) Describe how the sulphur trioxide is changed into concentrated sulphuric acid. [2] 6. In the USA, sulphur is obtained from underground deposits. It burns to form sulphur dioxide. This is used in paper making, to preserve food and in the manufacture of sulphuric acid. (i) Why is sulphur dioxide needed in paper making?... [1] (ii) How does sulphur dioxide preserve food?... [1] 1. Nitrogen dioxide, NO2, is a dark brown gas. 8) NITROGEN AND ITS COMPOUNDS (a) Most metal nitrates decompose when heated to form the metal oxide, nitrogen dioxide and oxygen. (i) Write a symbol equation for the decomposition of lead(ii) nitrate. 169

170 (ii) Potassium nitrate does not form nitrogen dioxide on heating. Write the word equation for its decomposition.... [1] (b) When nitrogen dioxide is cooled, it forms a yellow liquid and then pale yellow crystals. These crystals are heated and the temperature is measured every minute. The following graph can be drawn. (i) Describe the arrangement and movement of the molecules in the region A B (ii) Name the change that occurs in the region B C... [4] (c) Nitrogen dioxide and other oxides of nitrogen are formed in car engines. (i) Explain how these oxides are formed (ii) How are they removed from the exhaust gases? [4] (d) Nitrogen dioxide, oxygen and water react to form dilute nitric acid. Describe how lead(ii) nitrate crystals could be prepared from dilute nitric acid and lead(ii) oxide [3] 2. Ammonia contains the elements nitrogen and hydrogen. It is manufactured from these elements in the Haber process. 170

171 The forward reaction is exothermic. (a) (i) Nitrogen is obtained from liquid air by fractional distillation. Why does this technique separate liquid oxygen and nitrogen? (ii) Name two raw materials from which hydrogen is manufactured.... [3] (b) The table shows how the percentage of ammonia in the equilibrium mixture varies with pressure at 600 C. (i) Explain why the percentage of ammonia increases as the pressure increases [2] (ii) How would the percentage of ammonia change if the measurements had been made at a lower temperature? Explain your answer [2] (iii) State two of the reaction conditions used in the Haber Process [2] (c) Ammonia is a base. (i) Name a particle that an ammonia molecule can accept from an acid.... (ii) Write an equation for ammonia acting as a base.... [3] (d) Given aqueous solutions, 0.1mol/dm3, of sodium hydroxide and ammonia, describe how you could show that ammonia is the weaker base [2] 3. In 1909, Haber discovered that nitrogen and hydrogen would react to form ammonia. The yield of ammonia was 8%. (a) Describe how hydrogen is obtained for the modern process. [2] (b) (i) What is the catalyst in the modern process? [1] 171

172 (ii) Explain why the modern process, which uses a lower temperature, has a higher yield of 15%. [2] (c) (i) Complete the following table that describes the bond breaking and forming in the reaction between nitrogen and hydrogen to form ammonia. (ii) Explain, using the above data, why the forward reaction is exothermic. [2] 4. Ammonia is manufactured by the Haber Process. The forward reaction is exothermic. (a) (i) What is the catalyst for this reaction? [1] (ii) Newer catalysts have been discovered for this process. Using these catalysts, the operating temperature is lowered from 450 C to 400 C. What is the advantage of using a lower temperature? Explain your answer. advantage explanation [2] (b) After passing over the catalyst, the mixture contains 15% of ammonia. It is cooled and the ammonia liquefies and is separated from the unreacted nitrogen and hydrogen. They are recycled. (i) How are the gases recycled? [1] 172

173 (ii) Only ammonia gas liquefies. Suggest an explanation for this. [1] (c) Urea, CO(NH 2 ) 2, is one of the fertilisers manufactured from ammonia. Ammonia is heated with carbon dioxide. (i) Write an equation for the manufacture of urea. [2] (ii) Explain why urea on its own might not be very effective in promoting crop growth. [1] 9) STRUCTURE AND BONDING 1. It was reported from America that a turbine engine, the size of a button, might replace batteries. The engine would be built from silicon which has suitable properties for this purpose. (a) (i) Why are batteries a convenient source of energy? [1] (ii) The engine will run on a small pack of jet fuel. What other chemical is needed to burn this fuel? [1] (b) Silicon has the same type of macromolecular structure as diamond. (i) Explain why one atom of either element can form four covalent bonds. [2] 173

174 (ii) Predict two physical properties of silicon. [2] (iii) Name a different element that has a similar structure and properties to silicon. [1] (c) Silicon is made by the carbon reduction of the macromolecular compound, silicon (IV) oxide. (i) Balance the equation for the reduction of silicon(iv) oxide. (ii) Explain why the silicon(iv) oxide is said to be reduced. [1] (iii) Describe the structure of silicon(iv) oxide. You may use a diagram. [2] 2. Draw a diagram to show the arrangement of the valency electrons in one molecule of the covalent compound hydrogen sulphide. Use o to represent an electron from a sulphur atom. Use x to represent an electron from a hydrogen atom. 3. Another compound that contains nitrogen and hydrogen is hydrazine, N 2 H 4. (i) Draw the structural formula of hydrazine. Hydrogen can form only one bond per atom but nitrogen can form three. (ii) Draw a diagram that shows the arrangement of the valency electrons in one molecule of hydrazine. Hydrazine is a covalent compound. Use x to represent an electron from a nitrogen atom. Use o to represent an electron from a hydrogen atom. [3] 4. (a) The structure of a typical ionic compound is a regular arrangement of positive and negative ions. 174

175 (i) What is the name of this regular arrangement of particles? [1] (ii) Give two physical properties of ionic compounds. [2] (b) Ions are formed by electron loss or gain. The electron distribution of a magnesium atom is and of nitrogen atom is (i) Give the formula of the magnesium ion. [1] (ii) Give the formula of the nitride ion. [1] (iii) What is the formula of the ionic compound, magnesium nitride? [1] (iv) In this compound there is an ionic bond. Why are the two ions attracted to each other? [1] 5. The first three elements in Group IV are carbon, silicon, germanium (a) The element germanium has a diamond-type structure. Describe the structure of germanium. A diagram is acceptable. [2] (b) Unlike diamond, graphite is soft and is a good conductor of electricity. (i) Explain why graphite has these properties. [3] (ii) Give a use of graphite that depends on one of these properties. 175

176 property use [1] (c) Carbon dioxide and silicon (IV) oxide have similar formulae but different types of structure. (i) Give the formulae of these oxides. [1] (ii) How are their structures different? [2] (d) All these elements form compounds with hydrogen called hydrides. The saturated hydrides of carbon are the alkanes. Predict the formula of the hydride of germanium which contains two germanium atoms. [1] 6. The table shows the melting points, boiling points and electrical properties of the six substances A to F. (i) Which three substances are solids at room temperature? [1] (ii) Which one is an ionic compound? [1] (iii) Which one is a gas at room temperature? [1] (iv) Which two substances are liquids at room temperature? [1] (v) Which substance is a metal? [1] (vi) Which one is an impure substance? [1] 7. Give a diagram showing the arrangement of the valency electrons in one molecule of the covalent compound urea. Its structural formula is given below. 176

177 Use o to represent an electron from a carbon atom. Use x to represent an electron from a hydrogen atom. Use to represent an electron from a nitrogen atom. [3] 8. (a)the diagram shows a possible arrangement of the valency electrons in a molecule of sulphur dioxide. O represents an electron from an oxygen atom X represents an electron from a sulphur atom (b) Sulphur reacts violently with magnesium to form the ionic compound magnesium sulphide. Draw a diagram that shows the arrangement of the valency electrons in this compound. Use O to represent an electron from a magnesium atom. Use X to represent an electron from a sulphur atom. [3] 177

178 10) THE ATMOSPHERE 1. (a) Two of the gases in air are nitrogen and oxygen. Name two other gases present in unpolluted air. [2] (b) Two common pollutants present in air are sulphur dioxide and lead compounds. State the source and harmful effect of each. sulphur dioxide lead compounds (c) Respiration and photosynthesis are two of the processes that determine the percentage of oxygen and of carbon dioxide in the air. (i) Name another process that changes the percentages of these two gases in air. [1] (ii) The equation for photosynthesis is given below. This is an endothermic reaction. Complete the reaction for respiration. 178

179 (d) The rate of photosynthesis of pond weed can be measured using the following experiment. (i) Describe how you could show that the gas collected in this experiment is oxygen. [1] (ii) What measurements are needed to calculate the rate of this reaction? [2] (iii) What would be the effect, and why, of moving the apparatus further away from the light? [2] 2. Minimising air pollution is essential for health and for the environment. (a) Natural gas is methane. (i) Write the equation for complete combustion of methane. [2] (ii) Explain why it is dangerous to use a gas fire in a poorly ventilated room. [2] (b) Low sulphur fuels are being introduced. Ordinary diesel contains 500 ppm of sulphur but low sulphur diesel contains less than 50 ppm. Why is this an advantage to the environment? [2] (c) Catalytic converters reduce pollution from motor vehicles, as shown in the following diagram. 179

180 (i) What type of elements are the metals rhodium, platinum and palladium? [1] (ii) Rhodium catalyses the decomposition of the oxides of nitrogen. Two other pollutants are carbon monoxide and unburnt hydrocarbons. How are they made into less harmful substances? [2] 3. The poisonous gas, carbon monoxide, is emitted by vehicle exhausts. (i) How is this gas formed?... [2] (ii) Explain how a catalytic converter reduces the emission of this gas [2] 4. (a) (i) Describe how oxygen is separated from air [2] (ii) Give one use of oxygen.... [1] (b) When a green plant is exposed to bright light it photosynthesises and forms oxygen. The rate at which oxygen is formed was measured at 25 C. The intensity of the light is changed and the new rate measured. The results of experiments of this type are shown on the graph below. 180

181 (i) Write a word equation for the reaction that produces oxygen.... [1] (ii) Name the catalyst for photosynthesis.... [1] (iii) What can be deduced from this experiment about the relationship between photosynthesis and light? [2] (iv) The experiment was repeated at 30 C. Predict the effect this would have on the rate of reaction and sketch the new graph on the same axes. [2] (v) Give another example of a reaction that is influenced by light. Describe one important application of this reaction. reaction... application... [3] 181

182 11) ACIDS, BASES AND SALTS 1. The salt copper(ii) sulphate can be prepared by reacting copper(ii) oxide with sulphuric acid. Complete the list of instructions for making copper(ii) sulphate using six of the words below. 2. The Carlsbad caverns in New Mexico are very large underground caves. Although the walls of these caves are coated with gypsum (hydrated calcium sulphate), the caves have been formed in limestone. (a) It is believed that the caves were formed by sulphuric acid reacting with the limestone. (i) Complete the word equation. (ii) Describe how you could test the water entering the cave to show that it contained sulphate ions. test result [2] (iii) How could you show that the water entering the cave has a high concentration of hydrogen ions? [1] (b) Hydrogen sulphide gas which was escaping from nearby petroleum deposits was being oxidised to sulphuric acid. (i) Complete the equation for this reaction forming sulphuric acid. 182

183 (ii) Explain why all the hydrogen sulphide should be removed from the petroleum before it is used as a fuel. [1] 3. (i) Give a brief description of how the soluble salt, rubidium sulphate could be made from the soluble base, rubidium hydroxide. [3] (ii) Suggest a method of making the insoluble salt, calcium fluoride. [3] 4. (a) Four bottles were known to contain aqueous ammonia, dilute hydrochloric acid, sodium hydroxide solution and vinegar, which is dilute ethanoic acid. The bottles had lost their labels. The ph values of the four solutions were 1, 4, 10 and 13. Complete the table. (b) The following apparatus was set up to investigate the electrical conductivity of dilute acids. 183

184 Dilute sulphuric acid is a strong acid. If it was replaced by a weak acid, what two differences in the observations would you expect to make? [2] (c) When nitric acid is added to water the following reaction occurs. Give the name and the formula of the particle which is transferred from nitric acid to water. Name formula [2] (d) This question is concerned with the following oxides. (i) Which of the above oxides will react with hydrochloric acid but not with aqueous sodium hydroxide? [1] (ii) Which of the above oxides will react with aqueous sodium hydroxide but not with hydrochloric acid? [1] (iii) Which of the above oxides will react both with hydrochloric acid and with aqueous sodium hydroxide? [1] (iv) Which of the above oxides will react neither with hydrochloric acid nor with aqueous sodium hydroxide? [1] 5. (a) Insoluble compounds are made by precipitation. (i) Complete the word equation for the preparation of zinc carbonate. (ii) Complete the following symbol equation. 184

185 (iii) Write an ionic equation for the precipitation of the insoluble salt, silver (I) chloride. [2] (b) 2.0 cm 3 portions of aqueous sodium hydroxide were added to 4.0 cm 3 of aqueous iron (III) chloride. Both solutions had a concentration of 1.0 mol/dm 3 After each addition, the mixture was stirred, centrifuged and the height of the precipitate of iron(iii) hydroxide was measured. The results are shown on the following graph. 6. (a) (i) Write a symbol equation for the action of heat on zinc hydroxide. [2] 185