The real gases show deviations from ideal gas behaviour. It is observed that real gases donot follow Boyle's law, Charles law and Avogadro law perfectly under all conditions. The deviations from ideal behaviour can be measured in terms of compressiblity factor Z.
what is meant by the term Compressiblity ? (b) What is the value of Compressibility factor for ideal gases and real gases ?

Explanation

(a) Compressibility factor (Z) determines the extent of deviations of real gases from ideal gas beheviour. Mathmatical
`Z = (PV)/(mRT)` , (`PV = nRT` for ideal gas)
(b) For ideal gases `Z` = i.e., `PV = nRT`
For real gases `Z ne 1` , For negative deviations `(Z lt 1)` for positive deviations `(Z gt 1)`.
For details, consult section `5.18`