Worked example
Use Q = mcΔT. A 10 g sample with c = 2 J/(g·°C) warms by 3°C. What energy is transferred to it?
Answer & why
Answer: 60 J
10 × 2 × 3 = 60 J.
Grade 10 · Science
Use a simple thermal-energy model
Apply Q = mcΔT with supplied values and distinguish temperature change from total energy transfer.
6 authored questions + worked example
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All questions
All 6 authored questions for this skill.
Question 1
Use Q = mcΔT. A 5 g sample with c = 4 J/(g·°C) receives 100 J, with no other energy transfers. What is its temperature rise?
- 500°C
- 20°C
- 80°C
- 5°C
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: 5°C
ΔT = 100 ÷ (5 × 4) = 5°C.
Question 2
Two 10 g samples each warm by 2°C. A has c = 1 and B has c = 3 J/(g·°C). Which needs more energy in this model?
- They need equal energy.
- B, by a factor of 3.
- A, by a factor of 3.
- Neither needs energy.
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: B, by a factor of 3.
With mass and ΔT fixed, Q is proportional to c.
Question 3
A 20 g sample with c = 2 J/(g·°C) cools by 4°C. What magnitude of thermal energy leaves it in this model?
- 10 J
- 160 J
- 80 J
- 40 J
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: 160 J
The magnitude is 20 × 2 × 4 = 160 J.
Question 4
Two objects have the same temperature but different masses and materials. Does equal temperature alone establish equal thermal energy content?
- Yes; mass can never matter.
- Yes; all materials store identical energy.
- No; temperature can never be measured.
- No; temperature alone is insufficient.
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: No; temperature alone is insufficient.
Energy content depends on the amount and nature of matter as well as its state.
Question 5
Use Q = mcΔT. A 10 g sample with c = 2 J/(g·°C) warms by 3°C. What energy is transferred to it?
- 6 J
- 30 J
- 15 J
- 60 J
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: 60 J
10 × 2 × 3 = 60 J.
Question 6
A sample warms from 15°C to 23°C. What is ΔT?
- 23°C
- 8°C
- 38°C
- −8°C
A hint
Use the supplied mass and specific heat capacity; ΔT is the final temperature minus the initial temperature.
Answer & why
Answer: 8°C
Final minus initial gives 23 − 15 = 8°C.