Question

How is the partial pressure of a gas in a mixture calculated?

Answer 1

A law of partial pressures pertains.

Explanation:

In a gaseous mixture, the pressure exerted by a component is the same it would exert if this gas alone occupied the container. The total pressure is the sum of the individual partial pressures.

`P_(TOTAL) = P_1 + P_2 +...........P_N`

`=` `(n_1RT)/V + (n_2RT)/V +...........(n_nRT)/V`

`=` `((RT)/V)(n_1 +n_2 +...................n_n)`

Thus the pressure exerted by any component is proportional to the mole fraction:

`P_1` `=` `(RT)/Vxx` `n_1/(n_1 +n_2+n_3........+n_n)`

The constant of proportionality is `(RT)/V`.