How is the partial pressure of a component gas proportional to the percentage composition (by molar quantity) to the gaseous mixture?

1 Answer
Feb 14, 2017

Answer:

The partial pressure of each gas is proportional to the given percentage.

Explanation:

#P_"Total"=P_"methane"+P_"ethane"+P_"propane"+P_"butane"#.

Given the Ideal Gas equation, #P_"Total"=(n_"Total"RT)/V#

But #n_"Total"=(n_"methane"+n_"ethane"+n_"propane"+n_"butane")#

And so,

#P_"Total"=(n_"methane"+n_"ethane"+n_"propane"+n_"butane")(RT)/V#

You have the percentage composition of the gas, and you simply multiply #P_"Total"# by the individual percentages to get the partial pressure of each gas.

Thus #P_"methane"=1.48*atmxx94%=??*atm#. And you can work out these pressures individually.

See here for another example.