Many gas samples are not pure, but are mixtures of gases. So, to find the pressure exerted by each of them, this law is used.
By Sakshi Goel | 28 Oct'18 | 1 K Views |
Individual component in a gas mixture exerts a pressure which is called the partial pressure (Pn) of that component.
It can be calculated from the ideal gas law. For a multicomponent gas mixture, the partial pressure of each component can be computed as follows:
The sum of the partial pressures of the components in a gas mixture must equal the total pressure:
Ptotal = Pa + Pb + Pc +...
where Ptotal is the total pressure and Pa, Pb, Pc are the partial pressures of the components. This is known as Dalton’s law of partial pressures.
ntotal = na + nb + nc + ...
Relation between mole fraction and partial pressure:
Mole fraction of a is given as .
ntotal = na + nb + nc + ...