A student investigates the temperature change during the endothermic reaction between citric acid and sodium hydrogencarbonate solution. The results of this experiment are shown in the table below.
| Measurement | Temperature in ∘C^\circ\text{C}∘C |
|---|---|
| Temperature of sodium hydrogencarbonate solution at start | 20.2 |
| Minimum temperature of mixture at end | 11.4 |
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.