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Electrochemistry · CSEC Chemistry

135 past-paper questions on Electrochemistry, part of Principles of Chemistry, from every CSEC Chemistry paper on Quelpr.

Practise Electrochemistry
  1. 1(a)(i)2 marks· Chemistry Q1 1(a)(i)Define the term 'electrolysis'.
  2. 1(a)(ii)2 marks· Chemistry Q1 1(a)(ii)State TWO differences between the 'anode' and the 'cathode'.
  3. 1(a)(iii)3 marks· Chemistry Q1 1(a)(iii)Draw a diagram to show a circuit for carrying out this investigation. Label the cathode and the electrolyte.
  4. 1(a)(iv)2 marks· Chemistry Q1 1(a)(iv)Complete Table 1 by recording the mass of the cathode after 10 minutes and 20 minutes and the mass of copper deposited after 15 and 25 minutes.
  5. 1(a)(v)3 marks· Chemistry Q1 1(a)(v)Plot a graph of actual mass of copper deposited versus time using the axes in Figure 1 on page 5.
  6. 1(a)(vi)1 mark· Chemistry Q1 1(a)(vi)Use the graph to predict the mass of copper that would be deposited after 28 minutes.
  7. 1(a)(vii)2 marks· Chemistry Q1 1(a)(vii)Write an ionic equation to represent the reaction at the cathode.
  8. 1(a)(viii)2 marks· Chemistry Q1 1(a)(viii)Calculate the quantity of electricity that passed through the copper sulphate solution when 0.2 A of current flowed for 20 minutes. (Quantity of electricity = current × time; 1 F = 96 500 C)
  9. 1(a)(xi)1 mark· Chemistry Q1 1(a)(xi)Suggest a reason for the difference between the mass of copper obtained in (x) above and that recorded in Table 1.
  10. 1(a)(xii)1 mark· Chemistry Q1 1(a)(xii)The circuit used in this experiment was modified by replacing the copper electrodes with graphite electrodes. State ONE difference in the reaction at the anode when graphite electrodes are used.
  11. 1(f)(i)4 marks· Chemistry Q1 1(f)(i)An outline of the steps for a procedure you can use
  12. 1(f)(ii)2 marks· Chemistry Q1 1(f)(ii)A list of the main observations that would be expected at EACH stage of the experiment
  13. 2(a)(i)2 marks· Chemistry Q2 2(a)(i)Define the term 'electrolysis'.
  14. 2(a)(i)3 marks· Chemistry Q2 2(a)(i)In order to adapt the electrolytic cell in Figure 1 for the purification of copper, what material may be used as the cathode?
  15. 2(a)(i)2 marks· Chemistry Q2 2(a)(i)Define the term 'electrolysis'.
  16. 2(a)(ii)1 mark· Chemistry Q2 2(a)(ii)In order to adapt the electrolytic cell in Figure 1 for the purification of copper, what material may be used as the anode?
  17. 2(a)(ii)1 mark· Chemistry Q2 2(a)(ii)State the type of anode that is used in the purification of copper.
  18. 2(a)(ii)2 marks· Chemistry Q2 2(a)(ii)Define the term 'electroplating'.
  19. 2(a)(iii)3 marks· Chemistry Q2 2(a)(iii)List THREE other applications of electrolysis.
  20. 2(a)(iii)1 mark· Chemistry Q2 2(a)(iii)In order to adapt the electrolytic cell in Figure 1 for the purification of copper, what material may be used as the electrolyte?
  21. 2(b)1 mark· Chemistry Q2 2(b)At the anode, the hydroxide ions are discharged in preference to the sulphate ions. State a reason for this.
  22. 2(b)(i)1 mark· Chemistry Q2 2(b)(i)Which of the electrodes (Electrode 1 or Electrode 2) in the diagram is the cathode?
  23. 2(b)(i)4 marks· Chemistry Q2 2(b)(i)Draw a fully labelled diagram of the apparatus she should use and state the material from which the electrodes are made.
  24. 2(b)(i)3 marks· Chemistry Q2 2(b)(i)As electrolysis proceeds, describe the changes expected to be observed at the cathode.
  25. 2(b)(ii)1 mark· Chemistry Q2 2(b)(ii)Write the formula of the ion that migrates towards the anode.
  26. 2(b)(ii)4 marks· Chemistry Q2 2(b)(ii)Write balanced equations to indicate the reactions which occur at EACH electrode. Equation at anode: Equation at cathode:
  27. 2(b)(ii)1 mark· Chemistry Q2 2(b)(ii)As electrolysis proceeds, describe the changes expected to be observed at the anode.
  28. 2(b)(iii)2 marks· Chemistry Q2 2(b)(iii)Write a balanced ionic equation for the reaction occurring at the cathode.
  29. 2(b)(iii)1 mark· Chemistry Q2 2(b)(iii)As electrolysis proceeds, describe the changes expected to be observed in the electrolyte.
  30. 2(b)(iv)2 marks· Chemistry Q2 2(b)(iv)Explain why R will conduct electricity when molten but NOT in the solid state.
  31. 2(b)(v)4 marks· Chemistry Q2 2(b)(v)With reference to the electrochemical series, explain the difference in observations between Tests 3 and 4.
  32. 2(c)2 marks· Chemistry Q2 2(c)Write a balanced equation for the reaction at the anode.
  33. 2(c)3 marks· Chemistry Q2 2(c)With reference to the electrochemical series, predict what you may be expected to observe in Experiment 3. Give a reason for your answer.
  34. 2(c)(i)1 mark· Chemistry Q2 2(c)(i)Define the term 'electrolyte'.
  35. 2(c)(ii)2 marks· Chemistry Q2 2(c)(ii)Identify the ions that are produced from ethanoic acid during electrolysis.
  36. 2(c)(iii)1 mark· Chemistry Q2 2(c)(iii)Define the term 'cathode'.
  37. 2(c)(iv)1 mark· Chemistry Q2 2(c)(iv)Predict which ion from (c) (ii) will migrate to the cathode.
  38. 2(c)(v)3 marks· Chemistry Q2 2(c)(v)Is ethanoic acid a strong or weak electrolyte? Explain your answer.
  39. 2(e)2 marks· Chemistry Q2 2(e)State TWO changes that occur in the electrolyte.
  40. 2(e)2 marks· Chemistry Q2 2(e)In addition to extraction of metal from their compounds, electrolytic processes are also widely used to protect metals from corrosion, as well as to make them attractive. Name TWO such electrolytic processes.
  41. 2(e)(i)1 mark· Chemistry Q2 2(e)(i)State what effect this experimental arrangement will have on the bulb.
  42. 2(e)(ii)2 marks· Chemistry Q2 2(e)(ii)Explain your answer in (e)(i).
  43. 2(g)3 marks· Chemistry Q2 2(g)Indicate below how the apparatus in Figure 3 can be modified to obtain pure copper from impure copper. If no modification is required write “no modification required" in the relevant space. Anode: Cathode: Electrolyte:
  44. 3(a)4 marks· Chemistry Q3 3(a)Identify the processes which cause the bulbs to light in Experiments I and II. Explain how the processes differ.
  45. 3(b)1 mark· Chemistry Q3 3(b)Give the name of one substance which, if it replaces graphite in Experiment I, would cause the bulb NOT to light when the switch W is closed.
  46. 3(c)(i)4 marks· Chemistry Q3 3(c)(i)Provide a suitable explanation for the difference observed with Solutions P and Q.
  47. 3(c)(ii)1 mark· Chemistry Q3 3(c)(ii)Suggest a suitable substance for Solution Q.
  48. 3(d)(i)4 marks· Chemistry Q3 3(d)(i)What are the names of the parts of the apparatus labelled A and B in Experiment II?
  49. 3(d)(ii)4 marks· Chemistry Q3 3(d)(ii)What are the processes occurring at A and B?
  50. 4(a)2 marks· Chemistry Q4 4(a)Define 'electrolysis'.
  51. 4(a)(i)1 mark· Chemistry Q4 4(a)(i)What will happen to the bulb when the electrolyte is replaced with pure water?
  52. 4(a)(i)4 marks· Chemistry Q4 4(a)(i)State whether or not the bulb will glow for EACH substance. Explain your answer for EACH substance.
  53. 4(a)(i)2 marks· Chemistry Q4 4(a)(i)Identify TWO ions present in the electrolyte and include their state symbols.
  54. 4(a)(i)3 marks· Chemistry Q4 4(a)(i)Draw a fully labelled diagram of the apparatus which could be used in the electrolysis of molten BaBr₂. You should indicate the material from which the electrodes are made.
  55. 4(a)(i)1 mark· Chemistry Q4 4(a)(i)Define the term 'anion'.
  56. 4(a)(i)2 marks· Chemistry Q4 4(a)(i)Define the term 'electrolysis'.
  57. 4(a)(i)2 marks· Chemistry Q4 4(a)(i)On page 14, draw a fully labelled generalized diagram to show how the materials provided could be arranged to conduct the experiment in order to determine whether the substances tested are conductors or non-conductors.
  58. 4(a)(ii)1 mark· Chemistry Q4 4(a)(ii)Explain your answer to (a) (i).
  59. 4(a)(ii)4 marks· Chemistry Q4 4(a)(ii)Explain whether the oxides will conduct electricity and, if so, under what conditions.
  60. 4(a)(ii)1 mark· Chemistry Q4 4(a)(ii)What anions will be present in a sample of this electrolyte?
  61. 4(a)(ii)4 marks· Chemistry Q4 4(a)(ii)Write equations to indicate the chemical reactions which occur at the electrodes.
  62. 4(a)(ii)2 marks· Chemistry Q4 4(a)(ii)State TWO factors that affect the discharge of an ion in the electrolyte during electrolysis.
  63. 4(a)(ii)4 marks· Chemistry Q4 4(a)(ii)Describe what happens during the electrolysis of molten sodium chloride. Support your answer with relevant balanced ionic equations.
  64. 4(a)(ii)4 marks· Chemistry Q4 4(a)(ii)Complete Table 5 to indicate the observations that the students would have made when conducting the experiment.
  65. 4(a)(ii)a)3 marks· Chemistry Q4 4(a)(ii)a)State which substance causes the bulb to glow more brightly.
  66. 4(a)(ii)b)3 marks· Chemistry Q4 4(a)(ii)b)Explain why the substance you have stated at a) causes the bulb to glow brighter than the other substance.
  67. 4(a)(iii)4 marks· Chemistry Q4 4(a)(iii)By referring to the nature of the substances tested, provide a suitable explanation for EACH observation you recorded in (a) (ii) above. Write your answer in Table 5.
  68. 4(a)(iii)2 marks· Chemistry Q4 4(a)(iii)Predict which ions present in the electrolyte will be attracted towards the anode.
  69. 4(a)(iii)4 marks· Chemistry Q4 4(a)(iii)Draw a clearly labelled line diagram to represent an electrolytic cell.
  70. 4(a)(iii)2 marks· Chemistry Q4 4(a)(iii)Write a balanced ionic equation for the reaction occurring at the cathode for any of the substances in Pair 2.
  71. 4(a)(iv)2 marks· Chemistry Q4 4(a)(iv)List TWO factors which can in general affect the products formed during electrolysis of compounds.
  72. 4(a)(iv)2 marks· Chemistry Q4 4(a)(iv)Write a balanced equation for the reaction at the anode.
  73. 4(a)(v)2 marks· Chemistry Q4 4(a)(v)Write a balanced equation for the reaction at the cathode.
  74. 4(b)3 marks· Chemistry Q4 4(b)Aqueous sodium chloride can be electrolysed using inert electrodes. Discuss the effect that the position of ions in the electrochemical series has on the products of this electrolysis.
  75. 4(b)5 marks· Chemistry Q4 4(b)Calculate the volume of hydrogen gas liberated at STP, if a current of 965 A is passed through the circuit for 1 hour. (Q = I × t, F = 96 500 C mol⁻¹. At STP, 1 mol of gas occupies 22.4 L)
  76. 4(b)3 marks· Chemistry Q4 4(b)State whether EACH of the substances given in Table 2 are classified as conductors or non-conductors.
  77. 4(b)(i)2 marks· Chemistry Q4 4(b)(i)Solid sodium chloride
  78. 4(b)(i)2 marks· Chemistry Q4 4(b)(i)Draw a labelled diagram of apparatus which could be used in the electrolysis of molten MgI₂.
  79. 4(b)(i)1 mark· Chemistry Q4 4(b)(i)Why is the circuit as represented in Figure 5 not suitable to achieve the aim of the experiment?
  80. 4(b)(i)2 marks· Chemistry Q4 4(b)(i)Identify the gases in tubes A and B.
  81. 4(b)(i)2 marks· Chemistry Q4 4(b)(i)Define the terms 'electrolysis' AND 'cathode'.
  82. 4(b)(ii)4 marks· Chemistry Q4 4(b)(ii)Write equations to indicate the chemical reactions which will occur at EACH electrode.
  83. 4(b)(ii)2 marks· Chemistry Q4 4(b)(ii)1 mol dm⁻³ hydrochloric acid
  84. 4(b)(ii)2 marks· Chemistry Q4 4(b)(ii)Modify the diagram to produce a circuit that is suitable for achieving the aim of this experiment.
  85. 4(b)(ii)5 marks· Chemistry Q4 4(b)(ii)By considering the reactions that occur at the electrode surfaces, explain the occurrence of the 2:1 ratio in the gases collected in A and B. Use balanced ionic equations to support your answer.
  86. 4(b)(iii)2 marks· Chemistry Q4 4(b)(iii)Ethanol
  87. 4(b)(iii)2 marks· Chemistry Q4 4(b)(iii)Classify the three substances to be investigated (aqueous lead(II) nitrate, ethanol and aqueous ammonia) EITHER as conductors OR non-conductors.
  88. 4(b)(iv)2 marks· Chemistry Q4 4(b)(iv)A bar of lead touching the electrodes
  89. 4(c)6 marks· Chemistry Q4 4(c)Aluminium is made corrosion resistant by anodizing it. Using a labelled diagram and equations, explain what happens during the anodizing of aluminium.
  90. 4(c)4 marks· Chemistry Q4 4(c)Remi also wants to purify an impure nickel sample by electrolysis. Suggest how he could modify the line diagram drawn in (a) (iii) on page 16 in order to achieve this, and state ONE observation that would be expected.
  91. 4(c)5 marks· Chemistry Q4 4(c)A sample of molten lead bromide, PbBr₂, is electrolysed for three minutes with a current of 6 amperes. Calculate the mass of lead that is deposited at the cathode, given that two moles of electrons are required to…
  92. 4(c)(i)1 mark· Chemistry Q4 4(c)(i)If the bulb in Figure 3 is replaced with an ammeter, what will happen to the reading on the ammeter if the electrolyte is changed from dilute sulphuric acid to dilute methanoic acid?
  93. 4(c)(i)2 marks· Chemistry Q4 4(c)(i)Define the term 'electrolysis'.
  94. 4(c)(ii)2 marks· Chemistry Q4 4(c)(ii)Explain your answer to (c) (i).
  95. 4(c)(ii)6 marks· Chemistry Q4 4(c)(ii)Write the half equations, including state symbols, for the reaction that occurs at the anode and cathode during the electrolysis of concentrated sodium chloride solution (brine).
  96. 4(d)3 marks· Chemistry Q4 4(d)What adjustments have to be made to Figure 3 in order to copper-plate a spoon?
  97. 5(a)(i)2 marks· Chemistry Q5 5(a)(i)the name of the electrolyte and ions present
  98. 5(a)(i)2 marks· Chemistry Q5 5(a)(i)Name the TWO by-products.
  99. 5(a)(ii)2 marks· Chemistry Q5 5(a)(ii)an explanation for which ions are preferentially discharged at the electrodes
  100. 5(a)(ii)a)2 marks· Chemistry Q5 5(a)(ii)a)Write balanced ionic equations for the production of chlorine.
  101. 5(a)(ii)b)2 marks· Chemistry Q5 5(a)(ii)b)Write balanced ionic equations for the production of ONE of the named by-products in (i) above.
  102. 5(a)(iii)4 marks· Chemistry Q5 5(a)(iii)ionic equations showing the reactions at EACH electrode
  103. 5(a)(iv)1 mark· Chemistry Q5 5(a)(iv)the role of the ion exchange membrane in the diagram.
  104. 5(b)(i)4 marks· Chemistry Q5 5(b)(i)Explain what occurs at the anode and the cathode in the electrolysis of brine.
  105. 5(b)(i)1 mark· Chemistry Q5 5(b)(i)State what is expected to happen to the anode during the experiment.
  106. 5(b)(iii)4 marks· Chemistry Q5 5(b)(iii)Suggest why brine is used instead of dilute sodium chloride. Give an equation to justify your answer.
  107. 6(d)6 marks· Chemistry Q6 6(d)Predict the ions that will migrate to the anode and cathode during the electrolysis of dilute sulfuric acid (acidified water). Write a balanced chemical equation, including state symbols, for the electrolysis of dilute…
  108. Q311 mark · multiple choice· CSEC Chemistry · January 2017 · Paper 1During the electrolysis of aqueous copper(II) sulfate solution using inert electrodes, the ions migrating to the cathode are
  109. Q281 mark · multiple choice· CSEC Chemistry · January 2018 · Paper 1When a concentrated solution of sodium chloride is electrolysed using carbon electrodes,
  110. Q311 mark · multiple choice· CSEC Chemistry · January 2019 · Paper 1If substances containing one mole of solute per \text{dm}^3 are investigated, which substance should cause the bulb to glow BRIGHTEST?
  111. Q371 mark · multiple choice· CSEC Chemistry · January 2019 · Paper 1A current of 5 amperes was passed for 193 seconds through a solution of copper(II) sulfate using copper electrodes. [RAM: \text{Cu} = 65; Faraday's constant, F = 96\,500\text{ C mol}^{-1}] The mass of copper that…
  112. Q291 mark · multiple choice· CSEC Chemistry · May/June 2010 · Paper 1During the electrolysis of aqueous copper(II) sulphate solution using inert electrodes, the ions migrating to the cathode are
  113. Q321 mark · multiple choice· CSEC Chemistry · May/June 2010 · Paper 1What quantity of electricity passes through the electrolyte when a current of 100\text{ A} flows for 10 minutes?
  114. Q51 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the following ions requires the LARGEST number of moles of electrons to liberate one mole of it?
  115. Q281 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1If solutions containing one mole of solute per \text{dm}^3 of aqueous solution are investigated, which solution should cause the bulb to glow BRIGHTEST?
  116. Q291 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the following will NOT conduct electricity?
  117. Q301 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1A current of 5 amperes was passed for 193 seconds through a solution of copper (II) sulphate using copper electrodes. The mass of copper that would be gained at the (Relative atom mass of \text{Cu} = 64; Faraday…
  118. Q341 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1The reaction occurring at the cathode during the electrolysis of copper sulphate using inert electrodes is given by the equation
  119. Q351 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the following substances conducts an electric current but remains chemically unchanged?
  120. Q251 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Which of the following substances is a weak electrolyte?
  121. Q281 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Item 28 refers to the following apparatus which is used to investigate the relative conductivity of various substances. If solutions containing 1\text{ mole} of solute per \text{dm}^3 of aqueous solution are…
  122. Q291 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Which of the following substances does NOT conduct electricity?
  123. Q301 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Which of the following observations is expected with the electrolysis of concentrated sodium chloride solution using graphite electrodes?
  124. Q351 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Which of the following substances conducts an electric current and remains chemically unchanged?
  125. Q161 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1Which of the following substances, when added to pure water, SIGNIFICANTLY increases the water's conductivity?
  126. Q251 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1Which of the following observations is expected with the electrolysis of concentrated sodium chloride solution using graphite electrodes?
  127. Q271 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1In which of the following substances will electrolysis NOT occur when an electrical current is passed through it?
  128. Q481 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1Which of the following substances conducts an electric current but remains chemically unchanged?
  129. Q521 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1In which experiment would the amount of chlorine collected be GREATEST?
  130. Q231 mark · multiple choice· CSEC Chemistry · May/June 2016 · Paper 1In the electrolysis of aqueous copper(II) sulfate solution using copper electrodes, the anode
  131. Q281 mark · multiple choice· CSEC Chemistry · May/June 2016 · Paper 1Which of the following factors does NOT determine if a particular cation would be discharged during electrolysis?
  132. Q311 mark · multiple choice· CSEC Chemistry · May/June 2016 · Paper 1Which of the following statements about electrolysis is NOT correct?
  133. Q141 mark · multiple choice· CSEC Chemistry · May/June 2017 · Paper 1In which of the following substances will electrolysis NOT occur when an electrical current is passed through it?
  134. Q161 mark · multiple choice· CSEC Chemistry · May/June 2017 · Paper 1Which of the following substances, when added to pure water, SIGNIFICANTLY increases the water's conductivity?
  135. Q291 mark · multiple choice· CSEC Chemistry · May/June 2017 · Paper 1Which of the following does NOT take place during electrolysis?

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