What are the partial pressures of the gases?

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Answer 1 · 2016-11-01T03:39:40

In a gaseous mixture, the partial pressure exerted by a component gas is the same as the pressure it would exert if it alone occupied the container.

The total pressure is the sum of the individual partial pressures:

And thus #P_"total"=P_1+P_2+.........P_n#

Assuming ideality,

#(n_"total"RT)/V=(n_1RT)/V+(n_2RT)/V+.........(n_nRT)/V#

#(n_"total"RT)/V=(RT)/V{n_1+n_2..........+n_n}#

And thus the partial pressure of any component gas is proportional to the mole fraction, the constant of proportionality #=# #(RT)/V#.

Clearly, this law assumes a mixture of non-reacting gases. And thus now we breathe dioxygen gas at a pressure of approx. #0.20*atm#.