Specific Heat Capacity

    OCR
    GCSE

    Specific heat capacity is defined as the amount of energy required to raise the temperature of 1 kg of a substance by 1°C, mathematically expressed as ΔE = mcΔθ. This concept connects the macroscopic observation of temperature change to the microscopic increase in the kinetic energy of particles within a system. Candidates must demonstrate the ability to manipulate this relationship to solve for mass, temperature change, or energy, and must apply the concept to real-world thermal management systems such as engine coolants and domestic heating. Assessment frequently integrates the practical determination of specific heat capacity, requiring an understanding of electrical energy transfer (E = VIt) and the evaluation of systematic errors caused by thermal dissipation to the surroundings.

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    Objectives
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    Exam Tips
    3
    Pitfalls
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    Key Terms
    4
    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award 1 mark for correct substitution into the equation change in thermal energy = mass × specific heat capacity × temperature change.
    • Credit responses that explicitly state insulation (e.g., cotton wool, lagging) reduces energy transfer to the surroundings.
    • Award 1 mark for identifying that the calculated specific heat capacity will be higher than the true value if energy is lost to the surroundings.
    • Candidates must convert mass from grams to kilograms and energy from kilojoules to joules to gain full calculation marks.

    Example Examiner Feedback

    Real feedback patterns examiners use when marking

    • "You correctly selected the formula, but check your units—did you convert grams to kilograms?"
    • "Good calculation, but you missed the explanation marks. Why does the temperature not rise immediately when the heater is turned on?"
    • "You identified energy loss, but to get the mark, you must specify where the energy goes (e.g., 'to the surroundings')."
    • "Excellent rearrangement of the equation. To improve, explicitly state how adding a lid improves the accuracy of your result."

    Marking Points

    Key points examiners look for in your answers

    • Award 1 mark for correct substitution into the equation change in thermal energy = mass × specific heat capacity × temperature change.
    • Credit responses that explicitly state insulation (e.g., cotton wool, lagging) reduces energy transfer to the surroundings.
    • Award 1 mark for identifying that the calculated specific heat capacity will be higher than the true value if energy is lost to the surroundings.
    • Candidates must convert mass from grams to kilograms and energy from kilojoules to joules to gain full calculation marks.

    Examiner Tips

    Expert advice for maximising your marks

    • 💡When asked to improve the experiment, do not just say 'insulate it'—specify 'wrap the block in cotton wool' or 'place a lid on the beaker'.
    • 💡In 4-6 mark calculation questions involving Power (W), calculate the total Energy (J) using E = P × t before using the SHC formula.
    • 💡Check your units carefully: Specific Heat Capacity is measured in J/kg°C. If the question gives energy in kJ, multiply by 1000 first.

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Failing to convert mass from grams (g) to kilograms (kg) before substituting into the formula.
    • Stating vaguely that 'heat is lost' without specifying 'to the surroundings' or 'to the atmosphere'.
    • Confusing Specific Heat Capacity with Specific Latent Heat when describing changes of state versus changes in temperature.

    Study Guide Available

    Comprehensive revision notes & examples

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    Key Terminology

    Essential terms to know

    Definition and application of ΔE = mcΔθ
    Relationship between internal energy and temperature
    Practical determination using immersion heaters
    Conservation of energy and thermal dissipation

    Likely Command Words

    How questions on this topic are typically asked

    Calculate
    Explain
    Describe
    Suggest
    Determine

    Practical Links

    Related required practicals

    • •{"code":"PAG 1","title":"Determination of the Specific Heat Capacity of a material","relevance":"Core practical requiring setup of immersion heater, thermometer, and block/liquid"}

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