A student wants to collect hydrogen and oxygen using the electrolysis of sodium sulfate solution.
Some possible steps they can use in the electrolysis experiment are listed.
- Put filled, inverted test tubes over the electrodes to collect gases.
- Evaporate the final solution to dryness.
- Pour the sodium sulfate solution into the beaker.
- Put on safety goggles.
- Turn on the DC power supply.
- Heat the solid sodium sulfate until it melts.
Put the four steps that the student should use in the correct order.
□→□→□→□\Box \rightarrow \Box \rightarrow \Box \rightarrow \Box□→□→□→□
Oxygen is in Period 2 and Group 6 of the Periodic Table.
Which statements about oxygen are correct?
Tick (✓\checkmark✓) two boxes.
- Oxygen forms negative ions.
- Oxygen has 2 electrons in its outer shell.
- Oxygen has 6 electron shells.
- Oxygen has 6 electrons.
- Oxygen is a metal.
- Oxygen is a non-metal.
The student sets up another electrolysis experiment using copper(II) chloride solution, CuCl2\text{CuCl}_2CuCl2.
The table shows their results.
| Experiment | Mass of copper made (mg) | Volume of chlorine made (cm3\text{cm}^3cm3) |
|---|---|---|
| 1 | 12.8 | 4.5 |
| 2 | 25.6 | 9.0 |
| 3 | 38.4 | 13.5 |
| 4 | 51.2 | |
| 5 | 64.0 | 22.5 |
Estimate how much chlorine will be made in experiment 4.
Volume of chlorine made = ........................................................... cm3\text{cm}^3cm3
Describe the relationship between the amount of copper made and the amount of chlorine made.
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Copper(II) chloride solution is an electrolyte.
What type of compound is an electrolyte?
Tick (✓\checkmark✓) one box.
- Covalent
- Giant Molecular
- Ionic
Another student repeats the electrolysis experiment.
They record the mass of the electrode at the start of the experiment.
At the end of the experiment, they remove the electrode from the copper(II) chloride solution and record the mass immediately as shown in the diagram.
They notice that the mass is higher than they expect.
Suggest two changes the student could make to get a more accurate mass.
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