Question

The specific heat capacity is the property of a substance which determines the change in temperature of the substance due to exchange of heat energy with the surrounding. It is defined as the amount of heat energy absorbed or released per unit mass of the substance to change its temperature by one unit. Its SI unit is given by J kg-1K-1. Specific heat capacity of some substances at room temperature and atmospheric pressure is given by the table shown.

Suppose an amount of heat ΔQ supplied to a substance changes its temperature from T to T + ΔT. Heat capacity of a substance to be S = ΔQ/ΔT. We expect ΔQ and, therefore, heat capacity S to be proportional to the mass of the substance. Further, it could also depend on the temperature, i.e., a different amount of heat may be needed for a unit rise in temperature at different temperatures. To define a constant characteristic of the substance and independent of its amount, we divide S by the mass of the substance m in kg: s = S/m = (1/m) ΔQ/ΔT, s is known as the specific heat capacity of the substance. It depends on the nature of the substance and its temperature. The unit of specific heat capacity is J kg-1 K-1