The newest 6 of 6 written questions. Open one to see it on the real paper.
Solid citric acid is added to aqueous sodium hydrogencarbonate. There is a reaction and the temperature of the aqueous sodium hydrogencarbonate decreases. Plan an investigation to determine the relationship between the mass of citric acid added to the aqueous sodium hydrogencarbonate and the decrease in temperature. Yo...
See it on the paper →The reaction is endothermic. Use ideas about making bonds and breaking bonds in your answer. Explain what is meant by an endothermic reaction.
See it on the paper →At the end of the experiment the plastic cup contains: • • • a colourless solution a pink solid a grey solid. Explain how these observations show that the reaction has finished and that aluminium is in excess in this experiment.
See it on the paper →Electrolysis is an endothermic process. State the meaning of endothermic.
See it on the paper →During boiling, thermal energy (heat) is taken in. State the name for the type of process that takes in thermal energy.
See it on the paper →In an endothermic process heat energy is taken in from the surroundings. State if solid F dissolving in water is an endothermic process. Explain your answer using the results in Table 2.1.
See it on the paper →Many candidates found this question about endothermic reactions demanding. Some candidates referred to the energy required to break bonds, though many often referred to heat on its own, which is insufficient. Other candidates also referred to the energy released when new bonds are made. The best responses explained how the energy balance is endothermic overall.
— Examiner report, May/June 2025, 0653/42 Q5(a)(ii) (Cambridge)
This question proved to be demanding for most candidates and responses tended to repeat information that was given in the question rather than adding to it. Candidates needed to say the blue colour had disappeared and this was due to the absence of copper chloride. It was common for candidates to note the change of colour but not to link this to the absence of copper chloride. Similarly, candidate...
— Examiner report, May/June 2025, 0653/62 Q2(b) (Cambridge)
An endothermic process, one that takes in thermal energy from the surroundings, was stated correctly by many candidates. The most common incorrect answer was exothermic which is the process that gives out thermal energy.
— Examiner report, February/March 2025, 0653/32 Q6(f) (Cambridge)
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