Compressibility factor, Z, of a gas is given as Z = PV/ nRT
(i) What is the value of Z for an ideal gas?
(ii) For real gas what will be the effect on value of Z above Boyle’s temperature?
(i) Compressibility factor, Z is defined as the ratio of the product of pressure and volume to the product of number of moles, gas constant and temperature.
For ideal gas, the value of Z is 1.
Because, we know according to ideal gas equation,
PV = nRT
So, Z = 
= 
= 1
(ii) As at the temperature which is above the Boyle’s temperature, PV is greater than nRT for real gases so, the value of Z will also be greater than 1 i.e Z>1, which shows the positive deviation in the compressibility factor above Boyle’s temperature.
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