Grade OL Angel International SchoolManipay 2 nd Term Examination March, 2016 Chemistry Duration: 3 Hours 1. Which property is common to calcium, potassium and sodium? a) Their atoms all lose two electrons when they form ions b) They all form carbonates which are insoluble in water c) They are all less dense than water d) They all are metallic Index No:- 2. In the electrolysis of molten aluminum oxide for the extraction of aluminium, the following three reactions take place 1) Al 3+ + 3e Al 2) 2O 2- O 2 + 4e 3) C + O 2 CO 2 Which reactions take place at the anode? a) 1 only b) 2 only c) 1 and 3 d) 2 and 3 3. The diagram shows processes that take place in the manufacture of ammonia. Substance W cracking Hydrogen Substance X fractional distillation Nitrogen catalyst Y Ammonia What are the substances W and X and catalyst? a) W-air, X-oil, Y-iron b) W- air, X- oil, Y- vanadium(v) oxide c) W- oil, X- air, Y- iron d) W- oil, X- air, Y- vanadium(v) oxide
4. Which pair of elements, when combined together, do not form a covalent compound? a) Nitrogen and chlorine b) Phosphorous and fluorine c) Sulfur and chlorine d) Sodium and fluorine 5. The position of metal M in the reactivity series is shown. Decreases in reactivity K, Na, M, Al, Zn, Fe, Pb, Cu, Ag Which method will be used to extract M from its ore? a) Electrolysis of its aqueous sulfate b) Electrolysis of its molten oxide c) Reduction of its oxide by heating with coke d) Reduction of its oxide by heating with hydrogen 6. Why is carbon used in the purification of drinking water? a) It desalinates the water b) It disinfects the water c) It filters out solids d) It removes tastes and odors from the water 7. In the extraction of iron, carbon monoxide acts as a) A catalyst c) An oxidizing agent b) An inert gas d) A reducing agent 8. Which statement about catalysts is correct for a typical equilibrium reaction? a) A catalyst can be either an inorganic or organic species b) A catalyst does not take part in the reaction c) A catalyst only speeds up the forward reaction d) A catalyst provides the energy required to start a reaction 9. Natural gas, petroleum and diesel are all used as energy sources. Which gas is not produced when these sources are burned? a) Carbon dioxide c) Hydrogen b) Carbon monoxide d) Water 10.Element Z is in Group VI of the periodic table. Which formula is incorrect?
a) Z 2- b) Z 2 O 3 c) ZO 4 2- d) ZO 3 11.In the electrolysis of aluminium oxide to extract pure aluminium a compound called cryolite is first added to the oxide. What is the reason for adding the cryolite? a) To reduce the corrosion of the carbon electrodes by oxygen b) To reduce energy cost c) To enable the aluminium ions and oxygen ions to move to the electrodes d) To prevent the aluminium formed from being oxidized back to aluminium oxide 12.Which structure is not an isomer of the structure shown? CH3-CH2-CH2-CH2-CH3 a) CH3-CH2-CH-CH3 CH3 CH3 b) CH3-C-CH3 CH3 c) CH3-CH2-CH2-CH2 CH3 d) CH3-CH-CH2-CH3 CH3 13.Alkanes are a homologous series of organic compounds. Which statement about alkanes is correct? a) Their general formula is CnH2n b) They are unsaturated hydrocarbons c) Their boiling points increases as the length of the carbon chain increases d) They take part in addition reaction 14.Which of the following is an endothermic reaction? a) The combustion of ethanol in air b) Photosynthesis reaction c) The oxidation of carbon to carbon dioxide d) The reaction between hydrogen and oxygen 15.One mole of a sample of hydrated sodium sulphide contains 162g of water of crystallization. What is the correct formula of this compound. [O=16, H=1] a) Na 2 S.3H 2 O c) Na 2 S.7H 2 O b) Na 2 S.5H 2 O d) Na 2 S.9H 2 O
16.When a covalent liquid boils its molecules become more widely spaced. Which property of the molecules has the most influence on the energy required to boil a liquid? a) The forces of attraction between the molecules b) The reactivity of the molecules c) The shape of the molecules d) The strength of the covalent bonds in the molecules 17.The diagram shows the structure of the compound 1,3-butadiene. H2C CH CH CH2 How many moles of hydrogen are needed to saturate one molecule of 1,3- butadiene? a) 1 b) 2 c) 3 d) 4 18.Aluminium is used to make sauce pans because of its apparent lack of reactivity. Which property of aluminium explains its reactivity? a) It has a higher electrical conductivity b) It has a low density c) It has surface layer of oxide d) It is in Group III of the periodic table 19.A slow combustion in which glucose present in the body cells combine with oxygen to provide energy is a) Digestion c) Respiration b) Excretion d) None of the above 20.Which of the following reaction will not take place? a) Zn + FeSO 4 ZnSO 4 + Fe b) 2KI + Cl 2 2KCl + I 2 c) Zn + MgSO 4 ZnSO 4 + Mg d) Mg + CuSO 4 MgSO 4 + Cu 21.In the reaction, 2FeCl 2 + Cl 2 a) An oxidizing agent b) A reducing agent 2FeCl 3. Chlorine may be regarded as c) A catalyst d) Providing an inert medium 22.What is the concentration [moles per liter] of a solution in which 80 grams of sodium hydroxide NaOH is dissolved in 500cm3 of solution. a) 1moldm -3 c) 4moldm -3 b) 2moldm -3 d) 0.5moldm -3
23.A section of a polymer is shown. The structure of its monomer is H H The monomer undergoes condensation polymerization to form the polymer. What is made each time a monomer adds to the polymer? a) Hydrogen molecule, H 2 c) Oxygen atoms, O b) Hydroxide ions, OH - d) Water molecules, H 2 O 24.Ammonia gas is produced when solid ammonium chloride is heated with a) Calcium hydroxide c) Hydrochloric acid b) Calcium sulphate d) Magnesium nitrate 25.Which metal can react rapidly with steam, but reacts only very slowly with cold water? a) Iron c) Potassium b) Copper d) Magnesium 26.Sodium, aluminium and sulphur are in the same period of the periodic table. Which trend in types of oxide occurs across this period? a) Acidic amphoteric basic b) Amphoteric basic acidi c) Basic acidic amphoteric d) Basic amphoteric acidic 27.Which statement about the substance formed when a given mass of an element burns in excess oxygen is always correct? The substance formed is a) Denser than the element b) Greater in mass than the element c) Soluble in water d) White in colour 28.Which is a typical property of a transition metal? a) Low melting points b) Poor heat conductors when liquid c) Soft solid d) Very reactive
29.Solid ammonium chloride decomposes on heating according to the following reaction. NH 4 Cl(s) NH 3 (g) + HCl(g) litmus paper Porous plug Solid ammonium chloride heat Which change occurs to the damp red litmus paper in the experiment? a) Remains red b) Turns blue and is then bleached c) Turns blue and remains blue d) Turns blue and then turns red 30.A test tube containing a liquid X is placed in a beaker of boiling water. The liquid X starts to boil immediately. What is the boiling point of liquid X? a) 100 o c b) Above 100 o c c) Between 0 o c and room temperature d) Between room temperature and 100 o c 31.The table shows some properties of diamond and graphite. For which property is the reason correct? property Reason a Diamond cuts glass The bonds in glass are stronger than those in diamond b Diamond is a hard substance There are many ionic bonds in diamond c Graphite is a lubricant There are weak bonds between graphite layers d Graphite conducts electricity Graphite contains freely moving ions 32.Which metal is used in the sacrificial protection of iron pipes? a) Copper b) Lead c) Magnesium d) Sodium
Part 2 1) The structures of some substances containing nitrogen are shown below. N N H H H A B K+ NO 3 - NO 3 - K+ K+ NO 3 - I I I C N D N K+ NO 3 - K+ O N O E Answer the following questions by choosing from the structures A, B, C, D or E. You can use each structure once, more than once or not at all. Which structure represents I. An acidic oxide II. III. IV. An ionic structure. A gas which turns damp red litmus paper blue.. A compound which is formed under conditions of high temperature and pressure in car engines.. V. A molecule containing halogen atoms 2) Iron is a transition element. a. State three properties of transition elements which are not shown by the GroupI elements..
b. The symbols for two isotopes of iron are shown below. 54 57 Fe 26 26 Fe I. How do these two isotopes differ in their atomic structure?. II. III. Determine the number of neutrons present in one atom of the isotope Fe. Determine the number of electrons in one Fe 3+ ion?. c. Pure iron rusts very easily. I. Describe and explain one method of preventing rusting. II. Method explain why this method works. d. Iron can be recycled. Explain two advantages of recycling metals. e. In the blast furnace, iron(iii) oxide reacts with carbon monoxide. Fe2O3 + 3CO 2Fe + 3CO2 I. Which substance gets reduced in this reaction? Explain your answer. Substance. Explanation. II. III. Carbon monoxide is a pollutant gas produced in motor car engines. States why carbon monoxide is formed. States one harmful effect of carbon monoxide...
3) Ethanol, C 2 H 5 OH can be manufactured by two different processes. Process 1 the catalyzed addition of steam to ethene Process 2 the fermentation of glucose a) Name the type of reaction used to manufacture ethene... b) I. Write the equation for process 1.... II. Suggest the name of the alcohol made when the alkene C3H6 reacts with steam in the presence of a catalyst. c) The equation for process 2 is shown below. C 6 H 12 O 6 (aq) 2C 2 H 5 OH (aq) + 2CO 2(g) I. Describe two essential conditions required for efficient fermentation. II. Suggest one advantage of manufacturing ethanol by process 2 rather than by process 1... d) Process 2 makes an aqueous solution of ethanol. Suggest a method of purification that can be used to remove water from the aqueous ethanol... e) Describe a chemical test which could be used to positively identify the carbon dioxide formed during fermentation. Test Observation..
4) Choose from the following gases to answer the questions below [ammonia,butane, carbon dioxide, carbon monoxide, hydrogen, methane, nitrogen dioxide, oxygen] Which gas is I. The main constituent of natural gas II. Used by plants in photosynthesis to form glucose III. A product of incomplete combustion of hydrocarbons IV. Produced by Haber process... V. Formed at the cathode when an aqueous solution of sulphuric acid is electrolyzed.. VI. Acidic gases VII. Most reactive gas in atmosphere. 5) A solution of sodium hydroxide contained 0.25moldm -3. Using phenolphthalein indicator, titration of 25.0cm 3 of this solution required 22.5cm 3 of a hydrochloric acid solution for complete neutralisation. a) Write the equation for the titration the titration reaction b) What apparatus would be used to measure out I. The sodium hydroxide solution?.. II. The hydrochloric acid solution?.. c) What would you rinse your apparatus out with before doing the titration?.. d) What is the indicator color change at the end point? e) Calculate the moles of sodium hydroxide neutralized?
f) Calculate the moles of hydrochloric acid neutralized? g) Calculate the concentration of the hydrochloric acid in moldm- 3. 6) The carbonates of many metallic elements decompose when heated. a) Name the gas produced during the decomposition of a metal carbonate and describe a chemical test for this gas. b) Calcium oxide is manufactured by the decomposition of calcium carbonate. Write the equation for this decomposition... c) A student investigates the decomposition of five different metal carbonates. The diagram shows the apparatus the student uses. 100cm 3 gas syringe heat Metal carbonate
The student heats a 0.01mol sample of each carbonate using the blue flame of the same Bunsen burner. She measures time it takes for 100cm3 of gas to be collected in the gas syringe. The table shows her result carbonate Time taken to collect 100cm3 of gas Metal U carbonate 25 Metal V carbonate 100 Metal X carbonate 300 Metal Y carbonate No gas produced after 1000 seconds Metal Z carbonate 50 The student used calcium carbonate, copper(ii) carbonate, magnesium carbonate, sodium carbonate and zinc carbonate. Complete the table to show the identity of each metal U,V,X,Y and Z metal U V X Y Z Name of the metal d) Explain how you used the student s result to identify each metal. e) The nitrates of metallic elements also decompose when heated. Calcium nitrate decomposes to form calcium oxide, nitrogen dioxide and oxygen 2Ca(NO 3 ) 2(s) 2CaO(s) + 4NO 2(g) + O 2(g) A 0.01mol sample of calcium nitrate is heated. Calculate the number of moles of gas produced when this sample is completely decomposed.
7) A. This table shows some information about atoms of the elements W, X, Y and Z. [the letters do not represent the atomic symbols of the element] Element Atomic number Number of protons Number of neutrons Mass number Electronic configuration W 16 16 16 32 2,8,6 X 7 7 7 14 Y 1 1 1 2 Z 11 12 I. Complete the table by filling in the information for element Z. II. Give a reason why element Z is likely to be a metal. III. Describe the change in electronic configuration that occurs to an atom of element W when it forms an ion...... IV. Elements X and Y combine to form a covalently bonded molecule. Draw a dot and cross diagram to show the bonding in this molecule. Your diagram only needs to show outer electrons. B. This question is about the chemistry of the elements in period3 of the periodic table. I. Compare the reactions of sodium and magnesium with cold water. In each case identify the products formed.
II. Draw electronic structures, including the charges, of the ions present in sodium oxide. Hence deduce the formula for sodium oxide. III. Write an equation for the formation of aluminium oxide from its elements... IV. Pure sand is silicon(iv) oxide. It has a giant molecular structure similar to that of diamond. Suggest two physical properties of silicon(iv) oxide. 8) I. Give, and explain the electrode equations to show what is formed at the anode and cathode when electrical current is passed through an aqueous solution of sodium chloride...
II. What substance is left in solution and why is it an alkali?. III. Give the symbol equation for the reaction between sodium hydroxide and hydrochloric acid. What type of reaction is it?