Copper can be recovered from copper oxide by heating it with carbon.
2CuO+C→2Cu+CO22\mathrm{CuO} + \mathrm{C} \rightarrow 2\mathrm{Cu} + \mathrm{CO_2}2CuO+C→2Cu+CO2
Copper is the desired product.
| Substance | Relative atomic mass (ArA_rAr) or relative formula mass (MrM_rMr) |
|---|---|
| CuO\mathrm{CuO}CuO | 80 |
| C\mathrm{C}C | 12 |
| Cu\mathrm{Cu}Cu | 64 |
Calculate the percentage atom economy for making copper in this reaction.
Give your answer to 3 significant figures.
The process has a percentage yield of 92.0%.
A student says that 92.0% of the mass of the reactants becomes copper.
Explain why the student's statement is incorrect.
104 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.