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Specific heat capacity and latent heat questions

Calculate heating energy, temperature rise and changes of state; analyse electrical heating and stated energy losses.

Practise

Heating and changing state

A pure solid is melting at constant pressure. Its temperature remains constant while energy is transferred to it. What does that energy do?

Hint

During the change of state, energy changes the particle arrangement. Temperature is constant.

Worked solution
  1. Rule: Increases the potential-energy part of internal energy as the arrangement changes.
  2. Internal energy increases during melting.
  3. At constant temperature the average particle kinetic energy does not increase; the potential-energy contribution changes.
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Question type: Mixed practice
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Foundation and Higher: this set covers content common to both tiers. Some calculations need several steps.

Heating and changes of state

Use E = mcΔθ when temperature changes without a change of state. Use E = mL for a change of state at constant temperature. Specific heat capacity is measured in J kg⁻¹ °C⁻¹; specific latent heat in J kg⁻¹. Electrical input Pt may include energy transferred to the surroundings and apparatus. Only treat it as energy gained by the sample when the question states that assumption.

Work through the practical method and sample results

GCSE scope

AQA 8463: 4.1.1.3; 4.3.2.2–3; required practical 1 (selected); OCR Gateway J249: P1.2d–f; PM1.2i–ii; PAG P5 (selected). Tasks cover the selected skills listed above.

AQA specification · OCR Gateway specification