What is the unit of specific heat capacity?

J/kg °C (joules per kilogram per degree Celsius).

What does a high specific heat capacity tell you?

A lot of energy is needed to raise the temperature of 1 kg by 1 °C, so it warms up and cools down slowly.

Which has the higher specific heat capacity: water or aluminium?

Water (about 4200 J/kg °C compared with about 900 J/kg °C).

Final temperature minus starting temperature.

Name three ways energy is lost from a heated block.

Conduction, convection and radiation to the surroundings.

Why is c too high in an electrical heating experiment with heat loss?

The temperature rise is smaller than it should be, so c = Q ÷ (m ΔT) is too large.

How can heat loss be reduced in the experiment?

Wrap the block in insulation (lagging) or use a lid.

Specific heat capacityIB MYP Physics: Flashcards

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What is specific heat capacity?

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What is specific heat capacity?: The energy needed to raise the temperature of 1 kg of a substance by 1 °C.
What is the unit of specific heat capacity?: J/kg °C (joules per kilogram per degree Celsius).
State the equation linking energy, mass, specific heat capacity and temperature change.: Q = m c ΔT.
Rearrange Q = m c ΔT to make c the subject.: c = Q ÷ (m ΔT).
Rearrange Q = m c ΔT to make ΔT the subject.: ΔT = Q ÷ (m c).
What does a high specific heat capacity tell you?: A lot of energy is needed to raise the temperature of 1 kg by 1 °C, so it warms up and cools down slowly.
Which has the higher specific heat capacity: water or aluminium?: Water (about 4200 J/kg °C compared with about 900 J/kg °C).
How do you find ΔT?: Final temperature minus starting temperature.
Give two equations for the energy transferred by an electric heater.: E = P t and E = I V t.
How much energy does a 50 W heater transfer in 200 s?: 50 × 200 = 10 000 J.
Name three ways energy is lost from a heated block.: Conduction, convection and radiation to the surroundings.
Why is c too high in an electrical heating experiment with heat loss?: The temperature rise is smaller than it should be, so c = Q ÷ (m ΔT) is too large.
How can heat loss be reduced in the experiment?: Wrap the block in insulation (lagging) or use a lid.

Exam questions on Specific heat capacity

On a sunny afternoon in Dubai, the sand on a beach becomes too hot to walk on, while the sea water beside it feels pleasantly cool. Each kilogram of sand and each kilogram of sea water absorbs about the same amount of energy from the Sun.
Explain why the temperature of the sand rises by much more than the temperature of the sea water.2 marks
An electric kettle contains 1.5 kg of water at 20 °C. The heating element has a power of 2000 W. The specific heat capacity of water is 4200 J/kg °C, and the water must reach 100 °C to boil.
In practice the kettle takes longer than the time calculated. Explain why.2 marks
A student measures the specific heat capacity of aluminium using a block of mass 1.00 kg. The block has two holes: one holds a 12 V electric heater and the other holds a thermometer. The heater carries a current of 5.0 A for 300 s. The block is not insulated, and its temperature rises from 20.0 °C to 39.0 °C.
Calculate the specific heat capacity of aluminium from the student's results. Give your answer to three significant figures.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).