A reaction makes a desired product, X, and some waste products.
The relative formula mass of X is 60.
The atom economy for making X is 75%.
What is the total relative formula mass of the waste products in the balanced equation?
15
20
45
80
57 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.