Measuring enthalpy changes of reactions
2 marks · EasyExplain why it is important to stir the solution while measuring the temperature change in a calorimetry experiment.
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To ensure even heat distribution so all parts of the solution are at the same temperature; prevents inaccurate measurement due to local hot/cold spots.
Also accept: Ensures temperature is uniform; Makes results more accurate
Common mistakes: Saying 'to mix reactants' only
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Marking points
B1 · 1 mark · States stirring helps even out (or distribute) temperature or heat.
B1 · 1 mark · Explains this ensures the temperature measured is accurate OR that all solution is the same temperature (avoiding local hot/cold spots).
Worked solution
Stirring the solution allows heat to be evenly spread, so the whole mixture reaches a uniform temperature. This prevents hot or cold spots, making the temperature reading more accurate.