CCEA GCSE Chemistry. Questions and Answers. 2002/Paper 1

1. CEA Reward Learning GCSE 2002 Science: Chemistry Paper 1: Higher Tier

2. 1 A part of the Periodic table is shown below. a) Name the Russian scientist whose work led to the development of the modern Periodic Table. ___________________________ [1]

3. 1 A part of the Periodic table is shown below. a) Name the Russian scientist whose work led to the development of the modern Periodic Table. Mendeleev (similar spelling accepted) [1]

4. b) Using only the elements shown above name: (i) the most reactive Alkali Metal: ___________________________ [1] (ii) the least reactive Halogen: ___________________________ [1]

5. b) Using only the elements shown above name: (i) the most reactive Alkali Metal: rubidium [1] (ii) the least reactive Halogen: iodine [1]

6. (iii) the least dense Noble Gas: ___________________________ [1] (iv) a semi-metal ___________________________ [1]

7. (iii) the least dense Noble Gas: helium [1] (iv) a semi-metal silicon or germanium [1]

8. (v) a metal of valency 3: ___________________________ [1] (vi) two different elements which can exist as allotropes: ___________________________ [1]

9. (v) a metal of valency 3: aluminium [1] (vi) two different elements which can exist as allotropes: carbon [1] and sulphur [1] (Accept oxygen, phosphorus. Accept symbols for all (b) )

10. c) (i) Complete the table below to show the observations which could be made when the two selected elements react under the conditions shown. [13] Reaction with Magnesium Sulphur Oxygen Water/Steam No reaction Dilute hydrochloric acid

11. c) (i) Complete the table below to show the observations which could be made when the two selected elements react under the conditions shown. [13] Reaction with Magnesium Sulphur Oxygen Burns with (bright) white flame [1]; white [1] solid ash [1] remains Burns with blue flame [1]; pungent choking [1] gas [1] forms Water/Steam Burns in steam with (bright) white flame [1]; white [1] accept white/grey solid [1] remains No reaction Dilute hydrochloric acid Bubbles of colourless [1] gas/heat [1]; magnesium disappears [1] No reaction [1] accept an “X” blank box – no marks

12. (ii) Write balanced symbol equations for those reactions you think occur. _____________________________ _____________________________ _____________________________ __________________________ [8]

13. (ii) Write balanced symbol equations for those reactions you think occur. Mg + 2HCl -> MgCl 2 + H 2 [2] 2Mg + O 2 -> 2MgO [2] Mg + H 2 O -> MgO + H 2 [2] S + O 2 -> SO 2 [2] [1] – Correct symbols used throughout [1] – Correct balancing Accept correct ionic equation

14. 2 The methods used to prepare salts depend on whether the required salt is soluble or insoluble. Zinc sulphate, for example, is soluble while barium sulphate is insoluble.

15. a) (i) Describe in detail how you would prepare a pure dry sample of zinc sulphate crystals in the laboratory starting from solid zinc carbonate and dilute sulphuric acid. ________________________________ ________________________________ ________________________________ ________________________________ ____________________________ [10]

16. a) (i) Describe in detail how you would prepare a pure dry sample of zinc sulphate crystals in the laboratory starting from solid zinc carbonate and dilute sulphuric acid. Place a volume of dilute sulphuric acid in a beaker [1]. Warm acid [1]. Add/react/mix [1] zinc carbonate with stirring [1] until o more solid dissolves/no more gas is given off [1]. Filter [1] the mixture into an evaporating basin/beaker/crystallising dish [1]. Heat [1] the solution to reduce the volume [1]. Allow to cool [1], filter [1] decant off the crystals, desiccator/low temperature oven [1]. Do not accept – heat to dryness. (Max [10]/[13])

19. b) (i) Describe in detail how you would prepare a pure dry sample of barium sulphate in the laboratory starting with solutions of barium chloride and magnesium sulphate. ____________________________ ____________________________ ____________________________ ____________________________ _________________________ [5]

20. b) (i) Describe in detail how you would prepare a pure dry sample of barium sulphate in the laboratory starting with solutions of barium chloride and magnesium sulphate. Mix [1] the solutions of barium chloride and magnesium sulphate. A white [1] precipitate [1] formed. Filter [1] the mixture, rinse/wash with cold water [1] and dry in an oven [1]. Accept suitable drying method. (Max [5]/[6])

21. (ii) Give a balanced symbol equation for the preparation of barium sulphate. ________________________ [2] (iii) Give the names of two other compounds which could be used to make barium sulphate instead of barium chloride and magnesium sulphate. ________________________ [2]

22. (ii) Give a balanced symbol equation for the preparation of barium sulphate. BaCl 2 + MgSO 4 -> BaSO 4 + MgCl 2 Ba 2+ + SO 4 2- -> BaSO 4 [2] (iii) Give the names of two other compounds which could be used to make barium sulphate instead of barium chloride and magnesium sulphate . Barium nitrate [1] Any soluble sulphate [1] accept correct formula.

23. 3 Electrolysis plays an important part in extracting some metals from their ores and in purifying others. a) Define what is meant by the term electrolysis. _________________________________ ______________________________ [2] b) Name one metal which is obtained from its ore by electrolysis. ______________________________ [1]

24. 3 Electrolysis plays an important part in extracting some metals from their ores and in purifying others. a) Define what is meant by the term electrolysis. Electrolysis is decomposition [1] of a substance using an electric current [1] b) Name one metal which is obtained from its ore by electrolysis. Any reactive metal at the top of the reactivity series. Specification refers to aluminium [1]; but could accept sodium, potassium, calcium, magnesium, zinc.

25. c) Draw a labelled diagram of simple laboratory apparatus which shows how copper can be purified .

26. c) Draw a labelled diagram of simple laboratory apparatus which shows how copper can be purified . Complete circuit (1) (1) (1) Electrolyte (1) (1) (1) Accept any soluble copper salt

27. d) Write balanced , ionic equations to show the electrode reactions which occur when copper is purified. (i) At the anode ________________ [2] (ii) At the cathode ______________ [2]

28. d) Write balanced , ionic equations to show the electrode reactions which occur when copper is purified . (i) At the anode Cu -> Cu 2+ + 2e - [2] (ii) At the cathode Cu 2+ + 2e - -> Cu [2]

29. e) Which particles are responsible for the conductivity of electricity in: (i) metals? ____________________ [1] (ii) electrolytes? ________________ [1]

30. e) Which particles are responsible for the conductivity of electricity in: (i) metals? Electrons [1] (ii) electrolytes? Ions [1]

31. f) Give two uses of copper metal apart from its use in electrical wiring. _____________________________ ___________________________ [2]

33. g) The electrolysis of dilute sulphuric acid using inert electrodes produces two gases as products. (i) Name a material which could be used as the electrodes in this experiment. ___________________________ [1] (ii) Name the product formed at the anode _______________ cathode _____________ [2]

34. + - Comment Anode (+) Cathode (-) Ions attracted Ion discharged Ionic equation Observation

35. + - CARE: Comment Anode (+) Cathode (-) Ions attracted Ion discharged Ionic equation Observation

36. + - + - Comment Anode (+) Cathode (-) Ions attracted Ion discharged Ionic equation Observation

37. g) The electrolysis of dilute sulphuric acid using inert electrodes produces two gases as products. (i) Name a material which could be used as the electrodes in this experiment. Graphite (or platinum) [1] (ii) Name the product formed at the anode oxygen [1] accept O 2 cathode hydrogen [1] accept H 2

40. 4 a) What term is used to describe a reaction which gives out heat? __________________________ [1]

41. 4 a) What term is used to describe a reaction which gives out heat? Exothermic [1]

42. b) When drops of water are added to anhydrous copper sulphate heat is given out. (i) Describe what would be observed during this reaction. _________________________________ ______________________________ [2] (ii) The addition of water to anhydrous copper sulphate is called ______________________________ [1]

43. b) When drops of water are added to anhydrous copper sulphate heat is given out. (i) Describe what would be observed during this reaction. The white [1] solid would turn blue [1] (ii) The addition of water to anhydrous copper sulphate is called Hydration [1]

44. c) Heat is also given out during the reaction of sodium hydroxide with hydrochloric acid. (i) Give a balanced symbol equation for this reaction. ______________________________ [2] (ii) The reaction of an acid with an alkali is called ________________________ [1]

45. c) Heat is also given out during the reaction of sodium hydroxide with hydrochloric acid. (i) Give a balanced symbol equation for this reaction. NaOH + HCl -> NaCl + H 2 O [2] (ii) The reaction of an acid with an alkali is called Neutralisation [1]

46. d) The redox reaction of zinc with copper sulphate solution also gives out heat. (i) Describe what would be observed during this reaction. _________________________________ ______________________________ [2] (ii) Give a balanced symbol equation for this equation. _____________________ [2]

47. d) The redox reaction of zinc with copper sulphate solution also gives out heat. (i) Describe what would be observed during this reaction. The silvery/grey[1] zinc would become coated with red/brown[1] copper metal. The blue [1] solution fades / colourless / zinc disappears / bubbles[1] / green[1]. Max [2] (ii) Give a balanced symbol equation for this equation. Zn + CuSO 4 -> ZnSO 4 + Cu or Zn + Cu 2+ -> Zn 2+ + Cu [2]

48. (iii) The reaction of zinc with copper sulphate solution is an example of ______________________________ [1] (iv) Explain this redox reaction in terms of electron transfer. _________________________________ _________________________________ _________________________________ ______________________________ [5]

49. (iii) The reaction of zinc with copper sulphate solution is an example of Displacement [1] (iv) Explain this redox reaction in terms of electron transfer. The zinc has lost electrons [1] and is therefore oxidised [1]. The copper ions have gained electrons [1] and are therefore reduced [1]. Redox is reduction and oxidation taking place together [1]

50. To obtain full marks in this question, you must show your working out 5 When washing soda crystals, Na 2 CO 3 .10H 2 O, are left exposed to the atmosphere they lose water of crystallisation. The longer they are left, the more water is lost. The amount of water of crystallisation remaining can be found in two ways: either by heating to remove all the remaining water or by titration.

51. 5a) 2.675g of a sample of crystals were heated to constant mass. The mass of the residue was 1.325g. (i) Why was the sample heated to constant mass? ______________________________ [1] (ii) Calculate the number of moles of anhydrous sodium carbonate in the residue. ______________________________ [2]

52. Consequential marking applies throughout 5a) 2.675g of a sample of crystals were heated to constant mass. The mass of the residue was 1.325g. (i) Why was the sample heated to constant mass ? To ensure that all water [1] (of crystallisation) was lost. (ii) Calculate the number of moles of anhydrous sodium carbonate in the residue. Na 2 CO 3 = 1.325 = 0.0125 [1] 106 [1]

53. (iii) Calculate the mass of water lost and from this calculate the number of moles of water lost. _________________________________ ______________________________ [3] (iv) From your answers to part (a)(ii) and (iii) above, calculate the value of x in the formula Na 2 CO 3 .xH 2 O. _________________________________ ______________________________ [2]

54. (iii) Calculate the mass of water lost and from this calculate the number of moles of water lost. Mass of water lost = (2.765-1.325) g = 1.35g [1] Number of moles lost = 1.35 = 0.075 [1] 18 [1] (iv) From your answers to part (a)(ii) and (iii) above, calculate the value of x in the formula Na 2 CO 3 .xH 2 O. Ratio of moles Na 2 CO 3 : H 2 O 0.0125 : 0.075 [1] 1 : 6 [1]

55. b) 1.775g of a different sample of washing soda was dissolved in distilled water and made up of a total volume of 250cm 3 . 25.0cm 3 of this solution were titrated with 0.08 mol/dm 3 (moles per litre) nitric acid. 31.25cm 3 of acid were required. The equation for the reaction is: Na 2 CO 3 + 2HNO 3 -> 2NaNO 3 + H 2 O + CO 2 (i) Calculate the number of moles of nitric acid used in the titration. ______________________________________ ___________________________________ [2]

56. b) 1.775g of a different sample of washing soda was dissolved in distilled water and made up of a total volume of 250cm 3 . 25.0cm 3 of this solution were titrated with 0.08 mol/dm 3 (moles per litre) nitric acid. 31.25cm 3 of acid were required. The equation for the reaction is: Na 2 CO 3 + 2HNO 3 -> 2NaNO 3 + H 2 O + CO 2 (i) Calculate the number of moles of nitric acid used in the titration. Number of moles HNO 3 = 31.25 x 0.08 1000[1] = 2.5 x 10 -3

57. (ii) Calculate the number of moles of sodium carbonate present in the 25.0cm 3 sample. _______________________________________ ____________________________________[2] (iii) Calculate the number of moles of sodium carbonate present in 250cm 3 of solution. _______________________________________ ____________________________________[2]

61. c) Sodium hydrogencarbonate decomposes when it is heated into sodium carbonate according to the equation: 2NaHCO 3 -> NaCO 3 + H 2 O + CO 2 1.68g of sodium hydrogencarbonate were placed in a test tube and heated in a Bunsen flame for some time. (i) Calculate the number of moles of sodium hydrogencarbonate used. _______________________________________ ____________________________________ [2]

62. c) Sodium hydrogencarbonate decomposes when it is heated into sodium carbonate according to the equation: 2NaHCO 3 -> NaCO 3 + H 2 O + CO 2 1.68g of sodium hydrogencarbonate were placed in a test tube and heated in a Bunsen flame for some time. (i) Calculate the number of moles of sodium hydrogencarbonate used. Number of moles NaHCO 3 = 1.68 84 [1] = 0.02 [1]

63. (ii) Calculate the number of moles of sodium carbonate formed. ___________________________________ ________________________________ [2] (iii) Calculate the mass of sodium carbonate expected to be formed. ___________________________________ ________________________________ [2]

65. (iv) Calculate the volume of carbon dioxide produced in this experiment. (1 mole of gas occupies 24dm 3 at room temperature and pressure) _____________________________________ __________________________________ [2]

66. (iv) Calculate the volume of carbon dioxide produced in this experiment. (1 mole of gas occupies 24dm 3 at room temperature and pressure) Mole ratio NaHCO 3 : CO 2 2 : 1 [1] Number of moles CO 3 expected = 0.02 = 0.01 [1] 2 Volume of CO 3 expected = 24 x 0.01 = 0.24dm 3 [1] or 240cm 3