Practical questions
You will complete eight required practical activities if you are studying GCSE Chemistry, and 21 if you are studying GCSE combined science: Trilogy.
There are three required practicals in the Chemical Changes section:
- required practical 1 – preparation of a pure, dry sample of a soluble salt from an insoluble oxide or carbonate
- required practical 2 (chemistry only) – determination of the reacting volumes of solutions of a strong acid and a strong alkali by titration
- required practical 3 – investigate what happens when aqueous solutions are electrolysed using inert electrodes
There will be a number of different types of practical based questions. Some will be on the set required practicals, some will cover the working scientifically terms and some will be on other science practicals which you might have done in class. Use all the information given in the question particularly any diagrams to help you understand what the question is about.
Learn about practicals with Dr Alex Lathbridge
Listen to the full series on BBC Sounds.
Dr Alex Lathbridge answers questions about practicals.
Sample question 1 - Foundation
Question
A student does an electrolysis experiment.
He sets up the apparatus as shown in Figure 1.
He passes electricity through different solutions.
Figure 1
State an improvement the student can make to the circuit to show that a current is flowing.
[1 mark]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Connect a lamp/ammeter in series. [1]
Sample question 2 - Foundation
Question
A student investigated the reactivity of three different metals.
This is the method used.
- place 1 g of metal powder in a test tube
- add 10 cm3 of metal sulfate solution
- wait one minute and observe
- repeat using the other metals and metal sulfate solutions
The student placed a tick in table 1 if there was a reaction and a cross if there was no reaction.
Table 1
| Zinc | Copper | Magnesium | |
| Copper sulfate solution | ✔ | x | ✔ |
| Magnesium sulfate solution | x | x | x |
| Zinc sulfate solution | x | x | ✔ |
| Copper sulfate solution | |
|---|---|
| Zinc | ✔ |
| Copper | x |
| Magnesium | ✔ |
| Magnesium sulfate solution | |
|---|---|
| Zinc | x |
| Copper | x |
| Magnesium | x |
| Zinc sulfate solution | |
|---|---|
| Zinc | x |
| Copper | x |
| Magnesium | ✔ |
What is the independent variable in the investigation?
Tick one box.
[1 mark]
| A | Time taken | |
| B | Type of metal | |
| C | Volume of metal sulfate solution | |
| D | Whether there was a reaction or not |
| A |
|---|
| Time taken |
| B |
|---|
| Type of metal |
| C |
|---|
| Volume of metal sulfate solution |
| D |
|---|
| Whether there was a reaction or not |
This question is AQA material which is reproduced by permission of AQA.
| A | Time taken | |
| B | Type of metal | ✔ |
| C | Volume of metal sulfate solution | |
| D | Whether there was a reaction or not |
| A |
|---|
| Time taken |
| B |
|---|
| Type of metal |
| ✔ |
| C |
|---|
| Volume of metal sulfate solution |
| D |
|---|
| Whether there was a reaction or not |
Sample question 3 - Higher
Question
Sodium hydroxide neutralises hydrochloric acid.
The equation for the reaction is:
NaOH + HCl → NaCl + H2O
A student used a pipette to add 25.0 cm3 of sodium hydroxide solution of unknown concentration to a conical flask.
The student added hydrochloric acid. Describe how the student would complete the titration. You should name a suitable indicator and give the colour change that would be seen.
[4 marks]
This question is AQA material which is reproduced by permission of AQA.
- Add indicator, eg phenolphthalein/methyl orange/litmus to sodium hydroxide solution. [1]
- Add acid from burette... [1]
- ...with swirling or drop-wise near the end point until the indicator just changes colour. [1]
- Colour change is pink to colourless for phenolphthalein or yellow to red for methyl orange or blue to red for litmus. [1]
Sample question 4 - Higher
Question
A student investigated simple cells using the apparatus shown in figure 1.
Figure 1
- If metal 2 is more reactive than metal 1 then the voltage measured is positive.
- If metal 1 is more reactive than metal 2 then the voltage measured is negative.
- The bigger the difference in reactivity of the two metals, the larger the voltage produced.
The student's results are shown in table 1.
Table 1
| Metal 2 → | Chromium | Copper | Iron | Tin | Zinc |
| Chromium | Not measured | ||||
| Copper | 1.2 V | Not measured | |||
| Iron | 0.5 V | -0.1 V | Not measured | ||
| Tin | 0.8 V | -0.4 V | 0.3 V | Not measured | 0.6 V |
| Zinc | 0.2 V | -0.1 V | -0.3 V | -0.6 V | Not measured |
| Chromium | |
|---|---|
| Chromium | Not measured |
| Copper | |
| Iron | |
| Tin | |
| Zinc | |
| Copper | |
|---|---|
| Chromium | 1.2 V |
| Copper | Not measured |
| Iron | |
| Tin | |
| Zinc | |
| Iron | |
|---|---|
| Chromium | 0.5 V |
| Copper | -0.1 V |
| Iron | Not measured |
| Tin | |
| Zinc | |
| Tin | |
|---|---|
| Chromium | 0.8 V |
| Copper | -0.4 V |
| Iron | 0.3 V |
| Tin | Not measured |
| Zinc | 0.6 V |
| Zinc | |
|---|---|
| Chromium | 0.2 V |
| Copper | -0.1 V |
| Iron | -0.3 V |
| Tin | -0.6 V |
| Zinc | Not measured |
Look at table 1.
Which one of the metals used was the least reactive?
Give a reason for your answer.
[2 marks]
This question is AQA material which is reproduced by permission of AQA.
Copper was least reactive. [1]
Because:
It gave the most negative voltage when it was metal 2 or
It gave the biggest voltage with chromium or
It gave the most positive voltage when it was metal 1. [1]
