CalorimetryOxford AQA IGCSE Chemistry: Flashcards

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What is calorimetry?

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What is calorimetry?: The technique of measuring energy transferred in a reaction, usually via a temperature change.
Write the calorimetry equation.: Q = mcΔT.
What does each letter in Q = mcΔT stand for?: Q = energy transferred (J), m = mass (g), c = specific heat capacity (J/g°C), ΔT = temperature change (°C).
What units is energy measured in?: Joules (J) or kilojoules (kJ).
How many joules are in 1 kilojoule?: 1000 J.
Why is a metal container sometimes used instead of glass to measure combustion energy?: Metal conducts heat better, so more energy transfers to the water for measurement.
Why do experimental calorimetry values usually underestimate the true energy released by a fuel?: Some energy is lost to the surroundings rather than transferring fully to the water.
Why is an insulated container used when measuring the energy change of a reaction in solution?: To reduce energy loss to the surroundings and improve the accuracy of the temperature reading.
Give two types of solution reaction that calorimetry can be applied to.: Neutralisation reactions and reactions of solids with water.
What is specific heat capacity?: The energy needed to raise the temperature of 1 g of a substance by 1°C.
What temperature readings do you need to calculate ΔT in an experiment?: The starting temperature and the final temperature — the difference gives ΔT.
If 50 g of water rises in temperature by 10°C (c = 4.2 J/g°C), what is Q?: Q = 50 x 4.2 x 10 = 2100 J.