Fugacities in an imperfect gas mixture

For the ith component of an imperfect gas mixture the fugacity /i is chosen in such a way as to replace the partial pressure in equation (3 19). It is therefore defined by the following relations in which /ej 

In the imperfect mixture it is to be noted that both and/ depend on the nature and quantities of the other species wUch are present, i.e. they are functions of all of the partial pressures, as well as of the temperature. 

In equation (3 66) has the same value as for the pure gas i at the same temperature (equation (3 46)). If the mole fraction of this component is supposed to be progressively increased until it becomes equal to unity, the quantity remains unchanged, because 

An equation for the calculation of f from experimental data may be derived as in the previous section. From (2 111) 

Therefore, for any change of pressure at constant temperature and ctmpoaitum, d ,= F,dj . 

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