## Mayer’s relation – Mayer’s formula

Julius Robert Mayer, a German chemist and physicist, derived a relation between **specific heat at constant** pressure and the **specific heat at constant volume** for an ideal gas. He studied the fact that the specific heat capacity of a gas at constant pressure (C_{p}) is slightly greater than at constant volume (C_{v}). He reasoned that this *C***_{p}** is greater than the molar specific heat at constant volume

*C***, because energy must now be supplied**

_{v}**not only**to

**raise the temperature**of the gas but also for the

**gas to do work**because in this case volume changes. According to the

**Mayer’s relation**or the

**Mayer’s formula**the difference between these two heat capacities is equal to the universal gas constant, thus the molar specific heat at constant pressure is equal:

**C _{p} = C_{v} + R**