AQA · GCSE · Physics
Course version: 8463 · Version from Sept 2016
Students should be able to distinguish between specific heat capacity and…
Full specification wording
Changes of state and specific latent heat: Students should be able to distinguish between specific heat capacity and specific latent heat.
The two quantities answer different questions.
Checked against the AQA 8463 specification (opens in a new tab) on .
- Point 4 of 4
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The two quantities answer different questions. Specific heat capacity is the energy per kilogram to change the temperature by one degree with no change of state, unit J/kg °C, and it governs the sloping parts of a heating graph. Specific latent heat is the energy per kilogram to change state with no change of temperature, unit J/kg, and it governs the flat parts. Read the question for the giveaway words: warms, cools or rises from one temperature to another means c; melts, freezes, boils, condenses or evaporates means L. A problem that says ice at 0 °C is turned into water at 20 °C needs both, E = m L first at the plateau, then ΔE = m c Δθ up the slope.
What earns the marks
- Specific heat capacity involving a temperature change with no change of state.
- Specific latent heat involving a change of state with no temperature change.
- Contrasting the units, J/kg °C against J/kg.
- Matching each quantity to the sloping or flat section of a heating graph.
Common mistakes and how to put them right
Using ΔE = m c Δθ across the plateau of a heating graph, where the temperature is constant.
Inserting a temperature change into E = m L.
Quoting J/kg °C as the unit of specific latent heat.
Assuming a substance sitting at its melting point is receiving no energy because the thermometer reading is steady.
Exam tips
- Underline the verb in the question: melts and boils point to L, warms and cools point to c.
- State both differences when asked to distinguish them, what changes and what stays the same, not just the units.
- In a multi-stage calculation, set the work out as separate labelled stages so an examiner can award each part.
Try the lesson
The start of the Changes of state and specific latent heat: Students should be able to distinguish between specific heat capacity and specific latent heat. lesson, made from checked teaching notes for this specification point.
Have a go first
Which statement describes specific heat capacity rather than specific latent heat?
Listen
The two quantities answer different questions. Specific heat capacity is the energy per kilogram to change the temperature by one degree with no change of state, unit J/kg °C, and it governs the sloping parts of a heating graph. Specific latent heat is the energy per kilogram to change state with no change of temperature, unit J/kg, and it governs the flat parts. Read the question for the giveaway words: warms, cools or rises from one temperature to another means c; melts, freezes, boils, condenses or evaporates means L. A problem that says ice at 0 °C is turned into water at 20 °C needs both, E = m L first at the plateau, then ΔE = m c Δθ up the slope. A strong answer earns marks for these points. specific heat capacity involving a temperature change with no change of state. specific latent heat involving a change of state with no temperature change. contrasting the units, J/kg °C against J/kg. matching each quantity to the sloping or flat section of a heating graph. Exam tip: Underline the verb in the question: melts and boils point to L, warms and cools point to c.
Key words
Say what each word means before you turn the card.
specific heat capacity
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specific latent heat
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change of state
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heating graph sections
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See every definition
- specific heat capacity
- The energy per kilogram to change the temperature by one degree with no change of state, unit J/kg °C, governing the sloping parts of a heating graph.
- specific latent heat
- The energy per kilogram to change state with no change of temperature, unit J/kg, governing the flat parts of a heating graph.
- change of state
- A change such as melting, freezing, boiling, condensing or evaporating, in which specific latent heat is involved with no change of temperature.
- heating graph sections
- The sloping parts are governed by specific heat capacity and the flat parts by specific latent heat, where the temperature is constant.
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