A metal-recycling plant needs to collect 48.0 kg of pure metal R. Each process is supplied with the exact amounts of reactants required by its balanced equation, so neither reactant is in excess.
| Process | Atom economy / % | Percentage yield / % |
|---|---|---|
| P | 75 | 80 |
| Q | 90 | 60 |
| T | 65 | 95 |
Determine which process needs the smallest mass of starting materials to collect 48.0 kg of metal R. Calculate this mass to three significant figures.
151 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.