A quality-control laboratory checks four batches of salt solution. The batch records are shown.
| Batch | Solute | Mass of solute (g) | Volume of solution (cm3\mathrm{cm^{3}}cm3) |
|---|---|---|---|
| P | sodium sulfate, Na2SO4\mathrm{Na_2SO_4}Na2SO4 | 7.11 | 200 |
| Q | copper(II) sulfate, CuSO4\mathrm{CuSO_4}CuSO4 | 9.58 | 300 |
| R | magnesium chloride, MgCl2\mathrm{MgCl_2}MgCl2 | 7.15 | 250 |
| S | potassium chloride, KCl\mathrm{KCl}KCl | 4.48 | 250 |
Relative formula mass (MrM_rMr): Na2SO4\mathrm{Na_2SO_4}Na2SO4 = 142.1 CuSO4\mathrm{CuSO_4}CuSO4 = 159.6 MgCl2\mathrm{MgCl_2}MgCl2 = 95.3 KCl\mathrm{KCl}KCl = 74.6
Which batch should be labelled 0.300 mol/dm30.300\,\mathrm{mol/dm^{3}}0.300mol/dm3?
Batch S
Batch P
Batch Q
Batch R
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.