Figure shows the stages a company uses to make a chemical, and the mass of material at each stage.
Figure: The mass of material at each stage of making the chemical

The maximum theoretical mass of the pure product is 425 g. Calculate the percentage yield of the pure product.
Use Figure to calculate the mass of impurities removed during purification.
Explain why the mass of the pure product is less than the mass of the reactants, even though no atoms are lost in a chemical reaction.
39 exam-style questions on AQA GCSE Chemistry 3.3 Yield and atom economy of chemical reactions, covering 3.3.1a Percentage yield, 3.3.1b Theoretical mass of a product, 3.3.2a Atom economy, and 3.3.2b Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.