Practical questions

You will complete 21 required practical activities if you are studying GCSE combined science: Trilogy. You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.

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.

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.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

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.

Two carbon rods in a liquid and attached to a 6 v power charge.

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

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.

  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

ZincCopperMagnesium
Copper sulfate solutionx
Magnesium sulfate solutionxxx
Zinc sulfate solutionxx

What is the independent variable in the investigation?

Tick one box.

[1 mark]

ATime taken
BType of metal
CVolume of metal sulfate solution
DWhether there was a reaction or not
ATime taken
BType of metal
CVolume of metal sulfate solution
DWhether there was a reaction or not

Sample question 3 - Higher

Question

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]

Place four test tubes in a test tube rack. [1]

Label each bottle, and pour approximately 1 cm3 of solution from each bottle into a labelled test tube. [1]

Dip a separate piece of universal indicator paper into each test tube. [1]

Compare the colours of the indicator paper to the colours shown on the packet, and deduce the pH of each solution. [1]

The solution with the highest pH is 0.1 mol/dm3 ethanoic acid, and the solution with the lowest pH is 1.0 mol/dm3 hydrochloric acid. [1]

Sample question 4 - Higher

Question

A student investigated simple cells using the apparatus shown in figure 1.

Figure 1

Two rods of different metals connected to a power source and placed in a beaker of potassium nitrate solution.
  • 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 →ChromiumCopperIronTinZinc
ChromiumNot measured
Copper1.2 VNot measured
Iron0.5 V-0.1 VNot measured
Tin0.8 V-0.4 V0.3 VNot measured0.6 V
Zinc0.2 V-0.1 V-0.3 V-0.6 VNot measured

Look at table 1.

Which one of the metals used was the least reactive?

Give a reason for your answer. [2 marks]

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]