NATIONAL 5 CHEMISTRY

Farr High School NATIONAL 5 CHEMISTRY Unit 1 Chemical Changes and Structure Question Booklet 1

Rates of Reaction 1. Explain how the following would affect the rate of the reaction between 1.0 g of magnesium ribbon and an excess of 1.0 mol l -1 of hydrochloric acid at room temperature. (a) (b) (c) Using 1.0 g of magnesium powder. Using acid that has been stored in a fridge. Using 0.5 mol l -1 acid. 2. A pupil wanted to record data that would allow her to follow the speed of the reaction between zinc and hydrochloric acid. List three ways in which she could do this. 3. Look at the graph below and answer the following questions: a) What is the volume of gas produced after 20 seconds? b) What is the final volume of gas produced? c) At what time is the reaction complete (i.e. when it finished)? 2

4. The graph below shows how the volume of hydrogen gas given off changed with time during a reaction between pieces of zinc and dilute sulphuric acid. a) At what time was the reaction complete? b) Calculate the average rate of reaction over the first 20 second time period. c) Calculate the average rate of reaction between 20 seconds and 40 seconds. 5. A student carried out three experiments involving the reaction of magnesium with dilute acid. They measured the volume of hydrogen given off. The same mass of magnesium and volume of acid were used each time. A curve obtained for experiment 1 is drawn on the graph. Copy the above graph and draw 2 curves on the same axes to show the curves that would be obtained for experiments 2 and 3. Label each curve clearly. 3

6. Jean carried out an investigation into the rate of reaction of marble chips with dilute hydrochloric acid. She noted the loss in mass as carbon dioxide was given off, taking readings every minute. Her table of results is given below: a) Draw the experimental arrangement for measuring the rate of the reaction. b) Draw a graph of the results. c) Calculate the average rate over (i) (ii) the first 4 minutes? the full 8 minutes? 7. William and Sarah carried out an experiment to investigate the rate of reaction between 3.0g of calcium carbonate and an excess of 1 mol l -1 of hydrochloric acid. They monitored the reaction by measuring the volume of gas produced over time. (a) (b) (c) (d) Name the gas released in the reaction. Draw the apparatus required to carry out the experiment. The table below shows the results obtained. Draw a line graph of these results. Time (s) Volume of gas (cm 3 ) 0 0 10 20 20 40 30 56 40 70 50 82 60 90 70 96 80 100 90 102 100 102 Calculate the rate of reaction (i) (iii) over the first 20 seconds between 40 and 60 seconds (e) (f) (g) Why does the rate of the reaction decrease over time? At what time after the start did the reaction finish? The reaction was repeated, again using 1.5 g of calcium carbonate and an excess of 1.0 mol l -1 of hydrochloric acid. Draw a line on the graph to represent the results that you would expect for this experiment. 4

Atomic Structure and Bonding Related to Properties of Materials 1. Atoms are made up of protons, neutrons and electrons. The diagram below shows a model of an atom. Copy the diagram and label parts (a), (b) and (c). 2. Copy and complete the table to show the mass and charge of protons, neutrons and electrons. particle mass charge proton neutron 1 amu electron -1 3. The elements in the periodic table can be split into groups. Four of these groups are shown in the diagram below. Which group do the following elements belong to? a) sodium b) chlorine c) neon d) argon e) bromine f) iron g) potassium h) copper 5

4. An element has a mass number of 23 and an atomic number of 11. How many electrons are there in its atoms? 5. Look at the nuclide notation for the following atoms and write down the numbers of protons, electrons and neutrons in each one. 6. Name the element which has the following numbers of particles. a) 26 electrons, 29 neutrons, 26 protons b) 53 protons, 74 neutrons c) 2 electrons (neutral atom) d) 0 neutrons 7. Using a copy of the periodic table, copy and complete the table below. Nuclide notation Element Atomic Number Mass Number Protons Neutrons Electrons 56 26 Fe Iron 26 56 26 30 26 Phosphorus 15 16 15 Neon 10 10 Copper 35 29 19 20 7 7 47 61 Hydrogen 0 1 94 150 6

8. Copper has two isotopes, copper-63 and copper-65. (a) (b) What are isotopes? If the relative atomic mass of copper is given as 63.5, which isotope is in abundance? 9. Protium, deuterium and tritium are all isotopes of hydrogen. Their nuclide notations are shown below. (a) (b) How are the isotopes of hydrogen similar? How are the isotopes of hydrogen different? 10. Why are atoms electrically neutral? 11. Complete the diagrams below to show the electron configurations of the atoms. (Helium 2 electrons, Oxygen 8 electrons, Sulphur 16 electrons, Potassium 19 electrons) 7

12. What is meant by an ion? 13. Describe (a) how a sodium atom becomes a sodium ion (Na + ). (b) how a chlorine atom becomes a chlorine ion (Cl - ). (c) why argon does not form ions. 14. Use a copy of the periodic table and your knowledge of ions to complete the following table. Nuclide notation Element Protons Neutrons Electrons 56 3+ 26 Fe Iron 26 30 23 Nickel 31 26 82 125 80 Oxygen 8 10 Sodium 12 10 Calcium 20 18 Tin 69 50 Gold 118 76 15. (a) What is meant by the valency of an atom? (b) What is the valency of the following atoms? (i) magnesium (ii) bromine (iii) calcium (iv) oxygen (v) sodium 8

16. Oxygen forms diatomic molecules. (a) (b) What is meant by a diatomic molecule? What type of bonding takes place in oxygen molecules? 17. Draw dot and cross diagrams to show the outer electrons in the following covalent chemicals. For each molecule, suggest the likely shape. (a) fluorine F 2 (b) carbon dioxide CO 2 (c) ammonia NH 3 (d) methane CH 4 18. (a) Give the names of two chemicals which form covalent networks. (b) How do the melting and boiling points of chemicals which form covalent networks differ from those which form discrete covalent molecules? 19. Describe how lithium atoms combine with bromine atoms to form lithium bromide. You should use diagrams to help you. 20. Substance Electrical conductor Solution in Solid State Liquid State water State at 25 o C A yes yes insoluble liquid B no yes soluble solid C no no insoluble solid D yes yes insoluble solid E no no insoluble liquid From the table above, identify the substance which could be :- a) hexane b) candle wax (C 20 H 42 ) c) iron d) sodium chloride e) mercury 21. Look at the following information about potassium fluoride: Melting point 857 o C Boiling point 1502 o C Electrical conductor as a solid no Electrical conductor as a liquid or in solution yes Suggest the type of bonding present in potassium fluoride and give two pieces of evidence from the information above to support your answer. 9

22. Give the formula for the following covalent compounds: a) carbon monoxide b) sulphur dioxide c) carbon tetrafluoride d) dinitrogen trioxide e) nitrogen monoxide f) nitrogen trihydride 23. Write down the chemical formula for the following ionic compounds: a) sodium chloride b) sodium hydroxide c) calcium oxide d) calcium chloride e) hydrogen chloride f) magnesium fluoride g) iron (III) oxide h) potassium nitride i) copper (II) chloride j) aluminium iodide k) lithium chloride l) aluminium oxide m) barium sulphate n) aluminium nitrate o) magnesium carbonate p) sodium permanganate 24. Write down the ionic formula for the following compounds: a) iron (II) chloride b) copper (II) oxide c) magnesium sulphide d) aluminium nitride e) lithium nitrate f) magnesium nitrate g) sodium sulphate h) aluminium phosphate i) barium carbonate j) calcium hydroxide k) ammonium chloride l) potassium sulphite m) ammonium phosphate n) iron (II) permanganate o) sodium phosphate p) aluminium nitrate 10

Formulae and Reaction Quantities 1. Balance the following equations: a) SnO 2 + H 2 Sn + H 2 O b) KOH + H 3 PO 4 K 3 PO 4 + H 2 O c) KNO 3 + H 2 CO 3 K 2 CO 3 + HNO 3 d) Na 3 PO 4 + HCl NaCl + H 3 PO 4 e) TiCl 4 + H 2 O TiO 2 + HCl f) C 2 H 6 O + O 2 CO 2 + H 2 O g) Fe + HC 2 H 3 O 2 Fe(C 2 H 3 O 2 ) 3 + H 2 h) NH 3 + O 2 NO + H 2 O i) B 2 Br 6 + HNO 3 B(NO 3 ) 3 + HBr j) AlBr 3 + K KBr + Al k) P 4 + Br 2 PBr 3 l) PbBr 2 + HCl HBr + PbCl 2 m) CoBr 3 + CaSO 4 CaBr 2 + Co 2 (SO 4 ) 3 n) Na 3 P + CaF 2 NaF + Ca 3 P 2 o) Li 3 PO 4 + NaBr Na 3 PO 4 + LiBr p) HBr + Mg(OH) 2 MgBr 2 + H 2 O q) Mn + HI H 2 + MnI 3 r) LiNO 3 + CaBr 2 Ca(NO 3 ) 2 + LiBr s) Si(OH) 4 + NaBr SiBr 4 + NaOH t) NaCN + CuCO 3 Na 2 CO 3 + Cu(CN) 2 11

2. For each of the following compounds calculate the gram formula mass (mass of one mole in grams). a) sodium chloride b) sodium hydroxide c) calcium oxide d) calcium chloride e) hydrogen chloride f) magnesium fluoride g) iron (III) oxide h) potassium nitride i) copper (II) chloride j) aluminium iodide k) carbon dioxide l) methane 3. What is the mass (g) of: a) 2 moles of argon b) 0.5 moles of copper c) 3 moles of sodium chloride d) 0.2 moles of methane e) 10 moles of oxygen f) 0.25 moles of copper (II) oxide g) 0.01 moles of nitric acid [HNO 3 ] h) 0.25 moles of chlorine 4. Calculate how many moles are in: a) 14 g of nitrogen gas b) 20g of sodium c) 14.2 g of chlorine gas d) 16g of calcium e) 400g of copper (II) oxide f) 85g of lithium chloride g) 30g of aluminium sulphide h) 2.2g of carbon dioxide i) 84g of magnesium carbonate j) 321g of iron (III) hydroxide 5. Five moles of an unknown substance was found to weigh 325g. What was the gram formula mass of the substance? 6. (a) A substance has a gram formula mass of 95g. Its formula is XCI 2. What could element X be? (b) The substance X 2 O has a gram formula mass of 62 g. Identify element X. (c) A substance has the formula X(OH) 3 and a gram formula mass of 78g. Identify X. 12

7. (a) Calculate the mass of oxygen needed to produce 20.25 g of magnesium oxide. 2Mg + O 2 2MgO (b) (c) (d) (e) (f) (g) What mass of carbon dioxide is produced when 66 g of propane is burned in air. C 3 H 8 + 10O 2 3CO 2 + 4H 2 O What mass of water is produced when 160g of methane burns completely in air? CH 4 + 2O 2 CO 2 + 2H 2 O The fuel in a dragster is called nitromethane and it burns as follows: 4CH 3 NO 2 + 3O 2 4CO 2 + 6H 2 O + 2N 2 45kg of fuel is used in each race. Calculate the mass of oxygen required to burn this mass of fuel. What mass of iron would be produced by reducing 320 tonnes of iron (III) oxide in a blast furnace? Fe 2 O 3 + 3CO 2Fe + 3CO 2 Calculate the mass of water produced when 8g of hydrogen burns in oxygen. 2H 2 + O 2 2H 2 O Calculate the mass of iron (III) sulphide produced when 2.8g of iron reacts with excess sulphur. 2Fe + 3S Fe 2 S 3 8. What concentration of solution is obtained by dissolving: a) 5 moles of hydrogen chloride in 2 litres of solution b) 0.8 moles of copper sulphate in 200 cm 3 of solution c) 0.5 moles of lithium fluoride in 500 cm 3 of solution d) 1.25 moles of calcium nitrate in 2000 ml of solution e) 0.1 moles of nitric acid in 10 ml of solution f) 40 moles of potassium bromide in 100 litres of solution 9. What volume of solution is required to make: a) 0.4 mol l -1 solution containing 1 mole of sodium hydroxide b) 0.1 mol l -1 solution containing 0.05 moles of magnesium chloride c) 20 mol l -1 solution containing 4 moles of hydrogen peroxide d) 0.025 mol l -1 solution containing 0.02 moles of barium nitrate e) 2.25 mol l -1 solution containing 0.4 moles of ammonium bromide f) 6 mol l -1 solution containing 0.2 moles of sulphuric acid 13

10. How many moles are dissolved in: a) 500 ml of 0.5 mol l -1 sodium carbonate solution b) 3000 cm 3 of 2 mol l -1 barium chloride solution c) 5 litres of 0.1 mol l -1 zinc sulphate solution d) 250 cm 3 of 0.04 mol l -1 ammonium nitrate solution e) 600 ml of 3 mol l -1 hydrochloric acid solution f) 10 cm 3 of 0.2 mol l -1 potassium permanganate solution 11. For the following, calculate the number of moles of each substance and from this, calculate the mass of solid needed to make the following solutions: a) 500 ml of a 4 mol l -1 solution of potassium chloride b) 100 ml of a 0.4 mol l -1 solution of lithium hydroxide c) 2 litres of a 1.6 mol l -1 solution of magnesium fluoride d) 800 cm3 of a 1 mol l -1 solution of ammonium nitrate e) 50 litres of a 2 mol l -1 solution of sodium carbonate f) 10 ml of a 0.05 mol l -1 solution of aluminium sulphate g) 3 litres of a 0.6 mol l -1 solution of nickel (II) bromide h) 25 cm3 of a 0.1 mol l -1 solution of silver (I) nitrate 12. What is the concentration of solution if 10g of sodium hydroxide is dissolved in 3 litres of solution? 13. What concentration of solution is made by dissolving 16.4 g of calcium nitrate in 250 ml of solution? 14. What is the concentration of 100 cm 3 of ammonium hydroxide solution containing 0.7 g of dissolved solute? 15. What volume of 4 mole l -1 sulphuric acid solution contains 9.8 g of solute? 16. What volume of solution is required to make a 0.02 mol l -1 solution from 3.9 g of lithium fluoride? 17. What volume of solution is needed to make a 0.5 mol l -1 solution from 1.32 g of ammonium sulphate? 14

Acids and Bases 1. What do the following pieces of information tell you about the solutions? (a) Solution A turns universal indicator red. (b) Solution B has a ph of 8. (c) Solution C turns universal indicator purple. (d) Solution D has a ph of 7. 2. Do the following chemicals make acidic, alkaline or neutral solutions when they dissolve in water? (a) sodium chloride (b) sugar (c) hydrogen chloride (d) potassium hydroxide (e) carbon dioxide 3. Explain what is meant by dissociation. Use an equation to help. 4. How does the number of hydrogen ions (H + ) compare to the number of hydroxide ions (OH - ) in: a) a neutral solution? b) an acidic solution? c) an alkaline solution? 5. a) Give the names of: i) two strong acids ii) two weak acids b) In terms of dissociation, explain the difference between a strong and a weak acid. 7. Complete the table to show the difference in properties between strong and weak acids. Property Weak acid Strong Acid Electrical conductivity ph Reactivity 15

8. An alkali has a ph of 12. a) How will the concentration of hydrogen ions compare to the number of hydroxide ions in the solution? b) The solution is diluted with water. Explain what will happen to the ph of the solution. 9. A pupil used a sensor to record the change in ph of 10 cm3 of an acid solution when an alkali solution was added a little at a time. The concentrations of the alkali and acid solutions were fixed. His results are shown in the table below. volume of alkali added (cm3) ph of resulting mixture 0.0 5.0 2.0 5.0 4.0 5.0 6.0 5.5 8.0 6.0 10.0 7.0 12.0 8.0 14.0 8.5 16.0 9.0 18.0 9.0 20.0 9.0 (a) Use his results to draw a graph on a piece of graph paper. Label the axes. Plot the points. Draw a smooth curve. (b) Look at the graph. What would be the likely ph of the solution if the pupil added a further 2 cm3 of alkali solution? 16

10. Write a word equations for each of the following neutralization reactions: a) Potassium hydroxide reacting with sulphuric acid. b) Potassium hydroxide reacting with nitric acid. c) Potassium hydroxide reacting with hydrochloric acid. d) Calcium hydroxide reacting with hydrochloric acid. e) Magnesium oxide reacting with hydrochloric acid. f) Calcium hydroxide reacting with sulphuric acid. g) Calcium carbonate reacting with dilute sulphuric acid. h) Calcium carbonate reacting with dilute hydrochloric acid. i) Malachite (mainly copper carbonate) reacting with dilute sulphuric acid. j) Malachite reacting with dilute hydrochloric acid. 11. Write the word equation, a balanced formula equation and an ionic equation for the following reactions. Identify the spectator ions in the ionic equation. a) Lithium hydroxide solution and hydrochloric acid b) Calcium hydroxide solution and sulphuric acid c) Barium oxide solution and nitric acid d) Iron (II) oxide powder and hydrochloric acid e) Calcium carbonate lumps and sulphuric acid f) Lithium carbonate solution and nitric acid 12. In a reaction magnesium carbonate powder is used to neutralise 250 cm 3 of 2 mol l -1 dilute hydrochloric acid. a) How many moles of hydrochloric acid have been used in the experiment? b) The equation for the reaction is MgCO 3 (s) + 2HCl (aq) MgCl 2(aq) + H 2 O (l) +CO 2(g) Using your answer from part (a), calculate the number of moles of magnesium carbonate required to neutralise the dilute hydrochloric acid. c) Using your answer from part (b), calculate the mass of magnesium carbonate required to neutralise the dilute hydrochloric acid. 17

13. In a reaction calcium carbonate powder is used to neutralise 500 cm 3 of 0.5 mol l -1 dilute hydrochloric acid. a) How many moles of hydrochloric acid have been used in the experiment? b) The equation for the reaction is CaCO 3 (s) + 2HCl (aq) CaCl 2(aq) + H 2 O (l) +CO 2(g) Using your answer from part (a), calculate the number of moles of calcium carbonate required to neutralise the dilute hydrochloric acid. c) Using your answer from part (b), calculate the mass of calcium carbonate required to neutralise the dilute hydrochloric acid. 14. In a reaction sodium carbonate powder is used to neutralise 200 cm 3 of 2 mol l -1 dilute sulphuric acid. a) How many moles of sulphuric acid have been used in the experiment? b) The equation for the reaction is Na 2 CO 3(s) + H 2 SO 4(aq) Na 2 SO 4(aq) + H 2 O (l) +CO 2(g) Using your answer from part (a), calculate the number of moles of sodium carbonate required to neutralise the dilute sulphuric acid. c) Using your answer from part (b), calculate the mass of sodium carbonate required to neutralise the dilute sodium acid. 15. Calculate the concentration of sodium hydroxide if 50cm 3 of the alkali exactly neutralised 100cm 3 of 1 mol l -1 hydrochloric acid solution. 16. Calculate the volume of 0.25 mol l -1 sodium hydroxide if the alkali exactly neutralised 25 cm 3 of 0.5 mol l -1 hydrochloric acid solution. 17. Calculate the concentration of hydrochloric acid if 100cm 3 if the acid exactly neutralised 25cm 3 of 0.5 mol l -1 sodium hydroxide solution. 18. Calculate the concentration of sodium hydroxide if 50cm 3 of the alkali exactly neutralised 100cm 3 of 1 mol l -1 sulphuric acid solution. 19. Calculate the volume of 0.25 mol l -1 sodium hydroxide if the alkali exactly neutralised 50 cm 3 of 0.5 mol l -1 sulphuric acid solution. 20. Calculate the concentration of sulphuric acid if 25cm 3 if the acid exactly neutralised 25cm 3 of 0.5 mol l -1 sodium hydroxide solution. 18