A student investigates the temperature change when a sample of ammonium chloride dissolves in water. The results of this experiment are shown in the table.
| Measurement | Temperature in ∘C^\circ\text{C}∘C |
|---|---|
| Temperature of water at start | 19.3 |
| Minimum temperature of mixture at end | 13.5 |
Calculate the change in temperature. You must include a sign and a unit in your answer.
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.