Mayer's relation

In the 19th century, German chemist and physicist Julius von Mayer derived a relation between the molar heat capacity at constant pressure and the molar heat capacity at constant volume for an ideal gas. Mayer's relation states that $${\displaystyle C_{P,\mathrm {m} }-C_{V,\mathrm {m} }=R,}$$ where C_P,m is the molar heat capacity at constant pressure, C_V,m is the molar heat capacity at constant volume and R is the gas constant.