Which of these products is not a formulation?
A fertiliser made by mixing measured masses of three salts
A cleaning agent made by mixing measured volumes of liquids
A sample of nitrogen gas taken from a gas cylinder
An alloy made by mixing measured masses of two metals
40 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.