The compressibility factor (Z), also known as the compression factor, is the ratio of the molar volume of a gas to the molar volume of an ideal gas at the same temperature and pressure. It is a useful thermodynamic property for modifying the ideal gas law to account for the real gas behavior.
The compressibility factor is defined as:
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where is the molar volume, is the molar volume of the corresponding ideal gas, is the pressure, is the temperature, and is the gas constant.