A laboratory makes a lithium chloride solution by dissolving 5.30 g of lithium chloride in water and making the total volume up to 500 cm3\mathrm{cm^{3}}cm3.
Relative formula mass (MrM_rMr): LiCl\mathrm{LiCl}LiCl = 42.4
The solution is mixed thoroughly at each stage.
The solution is then processed as shown in the table.
| Stage | Operation |
|---|---|
| 1 | An 80.0 cm3\mathrm{cm^{3}}cm3 sample is taken from the original solution. |
| 2 | Water is added to this sample until its total volume is 200 cm3\mathrm{cm^{3}}cm3. |
| 3 | A 50.0 cm3\mathrm{cm^{3}}cm3 sample of the diluted solution is heated until some water evaporates and its total volume is 25.0 cm3\mathrm{cm^{3}}cm3. |
Calculate the concentration of the solution at the end of stage 3.
Give your answer in mol/dm3\mathrm{mol/dm^{3}}mol/dm3.
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.