Four different salts, W, X, Y and Z, are dissolved in water.
The table below shows the starting temperature of the water and the final temperature of the solution after each salt dissolves.
Complete the table:
| Salt W | Salt X | Salt Y | Salt Z | |
|---|---|---|---|---|
| Starting temperature in °C | 21.0 | 21.0 | 21.0 | 21.0 |
| Final temperature in °C | 24.5 | 19.2 | 25.2 | 17.5 |
| Temperature change in °C | +3.5 | −1.8 | ..... | ..... |
| Salt that absorbed the most heat energy when it dissolved |
94 exam-style questions on Edexcel GCSE Chemistry 8.2 Heat energy changes in chemical reactions, covering 8.2.1 Exothermic and endothermic changes, 8.2.2 Bond breaking, bond making and overall energy change, 8.2.3 Calculating energy change from bond energies, and 8.2.4 Activation energy and reaction profiles. Each one has a worked solution and a mark scheme showing where the marks go.