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 no required practical activities in the quantitative chemistry section. However, there may be some questions drawing on practical skills relating to this topic within other questions on the paper.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
A student does an experiment to find out the mass of copper sulfate she can make from a certain mass of copper oxide.
This is what she does:
Suggest two safety precautions she should take.
Give a reason for each precaution. [2 marks]
Wear eye protection to avoid substances getting into eyes. 
Do not touch hot apparatus to avoid burns. 
Name two pieces of apparatus suitable for measuring volumes of liquids or solutions. [2 marks]
Any two from:
A teacher demonstrates the reaction of hydrogen with oxygen.
This is what she does:
The reaction shown by the equation below occurred.
Fe2O3(s) + 2Al(s) → 2Fe(s) + Al2O3(s)
Which is the limiting reactant?
Show your working and explain your answer.
Use this data in your calculations:
Number of moles of iron oxide =
= 0.01 
Number of moles of aluminium =
= 0.03 mol 
The equation shows that 1 mole of iron oxide reacts with 2 moles of aluminium. 
This means that 0.01 mol of iron oxide reacts with 0.02 moles of aluminium.
The reactant that is used up completely is iron oxide, so this is the limiting reactant. 
A student added magnesium to dilute hydrochloric acid at 25 °C.
He measured the volume of hydrogen gas produced.
He repeated the experiment four more times and obtained the measurements below.
|Run 1 - Volume of gas obtained (cm3)||Run 2 - Volume of gas obtained (cm3)||Run 3 - Volume of gas obtained (cm3)||Run 4 - Volume of gas obtained (cm3)||Run 5 - Volume of gas obtained (cm3)|
a) Calculate the mean of the measurements in the table. [1 mark]
b) Calculate the range of the measurements in the table. [1 mark]
c) Estimate the uncertainty in the mean value. [1 mark]
a) Mean = cm3
= 21 cm3 
b) Range = 23 cm - 20 cm
= 3 cm 
c) Uncertainty in the mean =
= 1.5 cm