A company can make product M by three routes. In each route the starting materials are mixed in the ratio shown by the balanced equation, and any unreacted starting materials cannot be recovered.
| Route | Atom economy / % | Percentage yield / % |
|---|---|---|
| X | 100 | 40 |
| Y | 60 | 90 |
| Z | 80 | 60 |
The company wants the greatest mass of M from 100 kg of starting materials. Which route should it choose, and what mass of M does that route give?
Route X, 40 kg40\,\mathrm{kg}40kg
Route Y, 90 kg90\,\mathrm{kg}90kg
Route Y, 54 kg54\,\mathrm{kg}54kg
Route Z, 48 kg48\,\mathrm{kg}48kg
157 exam-style questions on Edexcel GCSE Chemistry 6.2 Quantitative analysis, covering 6.2.1 Concentration in mol dm⁻³ and titration calculations, 6.2.2 Percentage yield and why actual yield falls short, 6.2.3 Atom economy of a reaction, 6.2.4 Choosing a reaction pathway, and 6.2.5 Molar volume of gases and Avogadro's law. Each one has a worked solution and a mark scheme showing where the marks go.