Ideal and Real Gas relationship

At high pressures and lower temperatures, the gas molecules are more closely packed together and consequently intermolecular forces become more important. In such cases, the ideal gas equation needs to be replaced with more accurate equations. How the ideal gas equation can be modified to account for real gases?

The ideal gas equation is PV=mRT.

now based on whether the process is isentropic or adiabatic or isobaric or isochoric, then the P and V will be raised to powers of 1.4

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch4/deviation5.html