AQA GCSE Physics (8463), Higher tier · Particle model of matter › Internal energy and energy transfers
Practise Specific heat capacity. 15 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Complete the sentence. The specific heat capacity of a substance is the amount of energy needed to raise the temperature of ................ of the substance by ................ .
1 kg; 1 °C
Calculate the energy needed to increase the temperature of a 0.40 kg glass beaker by 25 °C. specific heat capacity of glass = 840 J/kg °C Use the equation: change in thermal energy = mass × specific heat capacity × temperature change
8400 J
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) Complete the sentence. The specific heat capacity of a substance is the amount of energy needed to raise the temperature of ................ of the substance by ................ .[2]
(b) Calculate the energy needed to increase the temperature of 2.0 kg of water by 15 °C. specific heat capacity of water = 4200 J/kg °C Use the equation: change in thermal energy = mass × specific heat capacity × temperature change[2]
Show the answer and mark scheme
(a)Answer: 1 kg; 1 °C
one kilogram / 1 kg
one degree Celsius / 1 °C
(b)Answer: 126 000 J
ΔE = 2.0 × 4200 × 15
126 000 (J)
Question 2Medium6 marks
An electric kettle transfers 151 200 J of energy to 0.60 kg of water. The water starts at a temperature of 18 °C. specific heat capacity of water = 4200 J/kg °C
(a) Calculate the final temperature of the water. Assume that all of the energy is transferred to the water. Use the Physics Equations Sheet.[3]
(b) The actual final temperature of the water was lower than the value you calculated. Give one reason why.[1]
(c) On a summer day, the temperature of the sea changes much less between day and night than the temperature of the land. Explain why. Use ideas about specific heat capacity.[2]
Show the answer and mark scheme
(a)Answer: 78 °C
151 200 = 0.60 × 4200 × Δθ
Δθ = 60 (°C)
final temperature = 18 + 60 = 78 (°C)
(b)Answer: Some of the energy heated the kettle itself and the surrounding air.
some of the energy was transferred to the kettle / to the surroundings / to the air
(c)Answer: Water has a much higher specific heat capacity than rock or soil, so much more energy must be transferred to change its temperature by each degree.
water has a higher specific heat capacity than the land / rock / soil
so more energy has to be transferred to (or from) each kilogram of water for each 1 °C change in temperature
Question 3Hard8 marks
A student heated a 0.20 kg copper block to 95 °C in a beaker of hot water. The student then quickly moved the block into 0.30 kg of water at 18 °C in an insulated cup. specific heat capacity of copper = 385 J/kg °C specific heat capacity of water = 4200 J/kg °C
(a) Explain why the temperature of the block decreases and the temperature of the water in the cup increases until they are the same.[2]
(b) Calculate the final temperature of the block and the water. Assume that no energy is transferred to the cup or to the surroundings. Give your answer to 3 significant figures. Use the Physics Equations Sheet.[4]
(c) The student measured the final temperature as 21.8 °C. Suggest two reasons why this was lower than the value calculated.[2]
Show the answer and mark scheme
(a)Answer: Energy is transferred from the hot block to the cooler water until both are at the same temperature, when there is no net energy transfer.
energy is transferred from the hotter block to the colder water (by heating)
until they are at the same temperature, when there is no longer a net transfer of energy
(b)Answer: 22.4 °C
energy transferred from the copper = energy transferred to the water
0.20 × 385 × (95 − T) = 0.30 × 4200 × (T − 18)
7315 − 77T = 1260T − 22 680 / 1337T = 29 995
T = 22.4 (°C)
(c)Answer: The block cooled while it was being moved, and some energy was transferred to the cup and to the surroundings.
the block cooled / transferred energy to the air while it was being moved to the cup
energy was transferred from the water to the cup / thermometer
energy was transferred from the water to the surroundings (the cup was not perfectly insulated / had no lid)