Chemistry 5070 · O Level · Exothermic and endothermic reactions
Exothermic and endothermic reactions — practice question
A student carries out an investigation into two fuels, hexane and octane. The student uses the apparatus shown to burn the fuels. In each experiment, a fixed volume of water is heated for five minutes. The diagrams display sections of the thermometer stem showing the starting and ending temperatures.
(a)[2]
Take the initial and final temperatures from the thermometer stems and enter them in the table. Then finish the table by working out the temperature changes.
(b)[1]
The student compares the temperature changes from the experiment with the correct values given in a data book. The student’s experimental values are smaller than the correct values. Suggest a reason, apart from student error, to explain why they are lower.
(c(i))[1]
In the investigation, which fuel releases more energy? Explain your answer.
(c(ii))[1]
What conclusion can be drawn from the temperature changes about the type of reaction taking place?
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct initial and final temperatures for hexane and octane” …