A student investigates the temperature change when ammonium nitrate dissolves in water.
The student uses 5.0 g of ammonium nitrate and 25 cm3 of water in each experiment. The temperature of the room remains at 20.0 ∘C20.0\ ^{\circ}\text{C}20.0 ∘C.
| Container | Lid | Starting temperature in ∘C^{\circ}\text{C}∘C | Lowest temperature in ∘C^{\circ}\text{C}∘C |
|---|---|---|---|
| Glass beaker | No lid | 20.0 | 15.5 |
| Polystyrene cup | Fitted lid | 20.0 | 12.5 |
Calculate the temperature change in each container.
Explain why the temperature fall is larger in the polystyrene cup with a fitted lid than in the glass beaker.
Predict whether the true temperature change is more negative or less negative than the temperature change you calculated for the polystyrene cup in part (a). Explain your answer.
106 exam-style questions on OCR GCSE Chemistry 3.2 Energetics, covering 3.2.1 Exothermic and endothermic reactions and reaction profiles and 3.2.2 Calculating energy change from bond energies. Each one has a worked solution and a mark scheme showing where the marks go.