中文（繁體）
中文（简体）
English
S6 Chemistry: Chemical Cells and Electrolysis (Paper 4: misconception drill)
S6 Chemistry: Chemical Cells and Electrolysis (Paper 4: misconception drill)
Ten drill items on the terminal joined to the cathode, the anode product from copper chloride, oxidation at both kinds of anode, copper from 0.100 mol of electrons, the volume ratio of hydrogen and oxygen, the mass gained in silver plating, moles and volume of chlorine, copper from 3.00 A for 1930 s, sodium from molten sodium chloride, and a misconception about oxygen at the cathode.
Direct answers Answers in order: the negative terminal, chlorine, yes, 3.18 g, 60.0 cubic centimetres, 21.6 g, 0.200 mol and 4.80 cubic decimetres, 1.91 g, 2.30 g, and hydrogen is released at the cathode.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S6 Chemistry: Chemical Cells and Electrolysis |
| Level | S6 |
02 Questions (10 items)
- FoundationWhich terminal of the supply is joined to the cathode of an electrolytic cell?
- FoundationWhat forms at the anode when copper(II) chloride solution is electrolysed with carbon electrodes?
- FoundationDoes oxidation occur at the anode in both galvanic and electrolytic cells?
- IntermediateWhen 0.100 mol of electrons passes through copper(II) chloride solution, what mass of copper deposits at the cathode (Cu = 63.5)?
- IntermediateWhen 120 cubic centimetres of hydrogen is collected at the cathode during the electrolysis of water, what volume of oxygen forms at the anode?
- IntermediateDuring silver plating 0.200 mol of electrons passes. By how many grams does the object gain mass (Ag = 108)?
- ChallengeWhen 0.400 mol of electrons passes through concentrated salt solution, how many moles and what volume of chlorine form at the anode at a molar volume of 24.0 cubic decimetres per mol?
- ChallengeA current of 3.00 A flows for 1930 s through copper(II) sulphate solution with carbon electrodes. What mass of copper deposits at the cathode (F = 96500, Cu = 63.5)?
- ChallengeDuring the electrolysis of molten sodium chloride 9650 C of charge passes. What mass of sodium forms at the cathode (Na = 23.0)?
- Error redoA student says oxygen is released at the cathode when dilute sulphuric acid is electrolysed. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | The negative terminal | Electrons flow from the negative terminal to the cathode so that cations there can be reduced. |
| 2 | Chlorine | Chloride ions lose electrons at the anode and are oxidised to chlorine. |
| 3 | Yes, the anode is where oxidation happens in both | The electrodes are named after the reaction, so the one where oxidation occurs is always called the anode. |
| 4 | 3.18 g | Each mole of copper needs two moles of electrons, so there is 0.0500 mol of copper and that times 63.5 is 3.18 g. |
| 5 | 60.0 cubic centimetres | The volume ratio of hydrogen to oxygen is two to one, so oxygen is half the volume of the hydrogen. |
| 6 | 21.6 g | Each silver ion takes one electron, so 0.200 mol of silver deposits and that times 108 is 21.6 g. |
| 7 | 0.200 mol, a volume of 4.80 cubic decimetres | Two moles of electrons give one mole of chlorine, so 0.400 divided by two is 0.200 mol and that times 24.0 is 4.80 cubic decimetres. |
| 8 | 1.91 g | 3.00 times 1930 gives 5790 C, which divided by 96500 is 0.0600 mol of electrons, so there is 0.0300 mol of copper and that times 63.5 is 1.91 g. |
| 9 | 2.30 g | 9650 divided by 96500 gives 0.100 mol of electrons, so there is 0.100 mol of sodium and that times 23.0 is 2.30 g. |
| 10 | Hydrogen is released at the cathode and oxygen at the anode | Water is reduced to hydrogen at the cathode and oxidised to oxygen at the anode. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Decide first whether the cell is galvanic or electrolytic, name the products at each electrode, then work through charge, moles of electrons and atomic mass in order.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.