1. Chemistry Chapter 8 –Chemical analysis – pure substances, formulations and testing for gases
Define the term pure substance .
Describe how to separate water and ethanol. Using distillation
Describe what a formulation, why they are important in medicines and give other examples.
Describe the difference between a pure substance and a mixture.
Describe how to separate 2 soluble substances.
State physical processes for separating mixtures.
State the tests for the below:
Oxygen –
Hydrogen –
Carbon dioxide –
Chlorine –
Draw 2 graphs to show a pure substance boiling and an impure substance boiling.
Describe briefly how to separation a solid from a solution using filtration and crystallisation

2. Chemistry Chapter 8 – Chemical analysis– RP and maths
State the equation to calculate Rf values.
Independent variable –
Dependent variable –
Control variables –
Describe a method used to investigate chromatography to identify ink mixtures. Include a diagram of your set up.
Write a risk assessment for this practical. Include the risk, hazard and control for at least 1 risk.
State the numbers below to 1 significant figure (sf) 41
8.6
0.478
0.74 15
State the numbers below to 2 sf.
0.589
457
8.45
89.5
102
State the numbers below to 3 sf.
0.7521
1589
896.7
97.82
102.6
Calculate the Rf value when the red spot moved 4.1 cm and the distance the solvent moved is 12.5cm. Show your working out.
Explain why some colours travel further than others.