A student measures the temperature rise for a neutralisation reaction. They record the temperature exactly 60 seconds after mixing. Their temperature rise is smaller than the true value. What is the most likely reason?
The thermometer was not read at eye level when the reading was taken
The acid and the alkali were both at room temperature before mixing
The reaction mixture was stirred with the thermometer before the reading
The maximum temperature was reached earlier and the mixture had begun to cool
39 exam-style questions on AQA GCSE Chemistry 5.1 Exothermic and endothermic reactions, covering 5.1.1 Energy transfer during exothermic and endothermic reactions, 5.1.2 Reaction profiles, and 5.1.3 The energy change of reactions. Each one has a worked solution and a mark scheme showing where the marks go.