CAIE A Level Chemistry 9701 · Atoms, molecules and stoichiometry
Acidified water was electrolysed using inert electrodes. The hydrogen and oxygen produced were collected and their volumes measured at the same temperature and pressure. The volume of hydrogen collected was twice the volume of oxygen collected.
Suggest what these measurements show about the stoichiometric relationship between hydrogen and oxygen, and what they indicate about the composition of water.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.
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