Extended · Practice questions · Specific heat capacity

Energy, mass, and a degree.

Six original Cambridge-style questions on the definition of specific heat capacity, calculations for energy and for c, why water is special, and the experiment to measure it.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
One equation, rearranged as needed

ΔE = m c Δθ.

01
[2 marks]

Define the specific heat capacity of a substance, and state its unit.

  • It is the energy needed to raise the temperature of 1 kg of the substance by 1 degree C (or 1 K). ✓
  • Unit: J/(kg degrees C), joules per kilogram per degree Celsius. ✓
02
Calculation
[3 marks]

Calculate the energy needed to raise the temperature of 0.5 kg of water from 20 degrees C to 80 degrees C. The specific heat capacity of water is 4200 J/(kg degrees C).

Δθ: 80 - 20 = 60 degrees C

ΔE = m c Δθ = 0.5 x 4200 x 60

ΔE = 126 000 J (126 kJ)

03
Calculation
[3 marks]

A 0.5 kg block of metal is given 9000 J of energy and its temperature rises by 40 degrees C. Calculate the specific heat capacity of the metal.

c = ΔE / (m Δθ) = 9000 / (0.5 x 40)

c = 9000 / 20

c = 450 J/(kg degrees C)

04
Calculation
[3 marks]

A heater supplies 27 000 J of energy to 1.5 kg of aluminium, of specific heat capacity 900 J/(kg degrees C). Calculate the rise in temperature, assuming no energy is lost.

Δθ = ΔE / (m c) = 27000 / (1.5 x 900)

Δθ = 27000 / 1350

Δθ = 20 degrees C

05
Analysis
[2 marks]

Water has a much higher specific heat capacity than most metals. Explain what this means in practice, and give one use that depends on it.

  • It takes a lot of energy to change water's temperature, so water heats up and cools down slowly. ✓
  • Used as a coolant (for example in car engines) or to carry heat in central heating systems. ✓
06
[3 marks]

Describe an experiment using an electrical heater to measure the specific heat capacity of a metal block. State the measurements you would take and how you would use them.

  • Measure the mass of the block, and place an electrical heater (and a thermometer) into it. ✓
  • Measure the energy supplied by the heater and the rise in temperature it produces. ✓
  • Calculate c = energy supplied / (mass x temperature rise). ✓

Insulate the block to reduce energy lost to the surroundings.

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.