Define state variables and equation of state .

Explanation

State variables : The variables which determine the thermodynamic behaviour of a system are called "state variables ".
If the system is a gas , then P, V and T (for a given mass ) are called state variables .
Equation of state : The general relationship between pressure volume and temperature for a given mass of the system (eg ., gas ) is called "equation of the state ."
For n moles of an ideal gas , the equation of state is , PV = nRT.