The
heat capacity of an object determines the
extent to which addition or removal of heat causes its
temperature to change.
Heat capacity (C) is the quantity of heat required to raise the temperature of an object by 1°C (or 1 K*). The heat capacity of an object depends both on the composition and the mass of the object.
Heat capacities are specific to the object in question and are usually determined experimentally.
| Substance | c/J g–1 K–1 |
| iron | 0.45 |
| air | 1.01 |
| water | 4.184 |
Specific heat capacity (
c) is the quantity of heat required to raise the temperature of 1 g of pure substance by 1°C (or 1 K*).
As might be expected, the specific heat capacity of a metal like iron is lower than air or water (that is, less heat is required to increase its temperature).
The
heat capacity of a given
mass of a
substance can be calculated from its specific heat capacity by multiplying by the mass.
C = c × m
This relationship may be used to calculate the heat capacity of a given mass or water or an aqueous solution.
The
heat capacity of the
collection of objects is the
sum of their individual heat capacities.
For example, in an experiment where a solution changes temperature, its container must also change temperature.
C(total) = C(solution) + C(container)
The
heat absorbed or released during a process can be calculated from the temperature change of the surroundings if the heat capacity of the substances and objects undergoing temperature change is known.
q(surroundings) = C(surroundings) × ΔT
ΔT = Tfinal - Tinitial