Heat Capacity Formula

Heat Capacity Formula

The heat capacity, or 'thermal mass' of an object, is defined as the Energy in Joules required to raise the temperature of a given object by 1º C. This is the 'specific heat' of the object (a defined physical/chemical property) multiplied by its mass and the change in temperature.

Heat capacity = mass x specific heat x change in temperature

Q = mc Δ T

Q = heat capacity, J

m = mass, g

c = specific heat of object, J/(g-ºC)

ΔT = change in temperature, ºC

Heat Capacity Formula Questions:

1) A 125-g piece of iron (specific heat = 0.45 J/gºC) is heated from 100 º C to 450º C. How much heat energy was required?

Answer: The mass, m = 125 g; the specific heat of iron, c = 0.45 J/gº C, and the change in temperature, ΔT, = 450 - 100 = 350 º C.

Q = mc Δ T

Q = (125 g) (0.45 J/gº C)(350 º C)

Q = 19687.5 J

2) If 15, 245 J of heat are applied to a copper ball with a mass of 45 g, how much will the temperature change? Specific heat of copper, c = 0.39 J/gº C.

Answer: The mass, m = 45 g; the specific heat, c = 0.39 J/gº C; and Q = 15245 J.

Q = mc Δ T

Q/mc = Δ T

(15245 J) / (45 g)(0.39 J/gº C) = Δ T

ΔT = 868.66 º C

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