Hydrogen peroxide is decomposed to make oxygen, which is the desired product. The water that forms is not needed.
2H2O2→2H2O+O2 \mathrm{2H_{2}O_{2} \rightarrow 2H_{2}O + O_{2}} 2H2O2→2H2O+O2| Quantity | Value |
|---|---|
| Mr M_r\,Mr of H2O\mathrm{H_2O}H2O | 18.0 |
| Mr M_r\,Mr of O2\mathrm{O_2}O2 | 32.0 |
| Mass of hydrogen peroxide decomposed in one batch | 8.50 kg |
Use the equation:
atom economy=Mr of desired productsum of Mr of all products×100 \text{atom economy} = \frac{M_r \text{ of desired product}}{\text{sum of } M_r \text{ of all products}} \times 100 atom economy=sum of Mr of all productsMr of desired product×100Calculate the atom economy for making oxygen.
Calculate the maximum mass of waste water made in one batch.
152 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.