Specific Heat Capacity

Question 1

Specific heat capacity is the heat needed to raise the temperature of

Accepted Answer

1 kg of a substance by 1 °C — By definition it refers to 1 kg and a 1 °C rise.

Question 2

The correct equation for heat absorbed is

Accepted Answer

Q = mcθ — Heat = mass × specific heat capacity × temperature change.

Question 3

The SI unit of specific heat capacity is

Accepted Answer

J kg⁻¹ °C⁻¹ — It is heat per kilogram per degree Celsius.

Question 4

How much heat is needed to raise 2.0 kg of water by 30 °C? (c = 4200 J kg⁻¹ °C⁻¹)

Accepted Answer

252 kJ — Q = 2.0 × 4200 × 30 = 252 000 J = 252 kJ.

Question 5

Water is a good coolant mainly because it has a

Accepted Answer

high specific heat capacity — High c lets it absorb much heat with a small temperature rise.

Question 6

A material with a low specific heat capacity will

Accepted Answer

heat up quickly — Low c means little heat is needed for a big temperature rise.

Question 7

The heat supplied to 0.5 kg of a metal raises its temperature by 20 °C using 3900 J. Its specific heat capacity is

Accepted Answer

390 J kg⁻¹ °C⁻¹ — c = Q/(mθ) = 3900/(0.5 × 20) = 390 J kg⁻¹ °C⁻¹.

Question 8

In the formula Q = mcθ, the symbol θ represents the

Accepted Answer

change in temperature — θ is the temperature change, not an absolute reading.

Question 9

Sea breezes during the day occur because

Accepted Answer

the land heats faster than the sea — Land has a lower specific heat capacity, so it warms faster.

Question 10

If the same amount of heat is given to equal masses of water and oil (oil has lower c), which rises more in temperature?

Accepted Answer

Oil — Lower specific heat capacity gives a larger temperature rise.