Sample exam questions - chemical changes - AQAPractical questions

A student does an electrolysis experiment.

He sets up the apparatus as shown in Figure 1.

He passes electricity through different solutions.

State an improvement the student can make to the circuit to show that a current is flowing. [1 mark]

A student investigated the reactivity of three different metals.

This is the method used.

1. Place 1 g of metal powder in a test tube.
2. Add 10 cm³ of metal sulfate solution.
3. Wait 1 minute and observe.
4. 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

What is the independent variable in the investigation?

Tick one box.

[1 mark]

A student has three acidic solutions, listed below:

• 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.
• In your answer state the apparatus needed and how to use the results to identify the acids.

The solutions are in unlabelled bottles.

Describe how the student could use universal indicator paper to find out which acid is which. [5 marks]

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

Look at table 1.

Which one of the metals used was the least reactive?

Give a reason for your answer. [2 marks]