Consider a mixture of two gases, A and B, confined in a closed vessel. A quantity of a third gas, C, is added to the same vessel at the same temperature. How does the addition of gas C affect the following: (a) the partial pressure of gas A, (b) the total pressure in the vessel, (c) the mole fraction of gas B?

c the mole fraction of gas B

(b) the total pressure in the vessel and (c) the mole fraction of gas B

Explanation:

First off, it's important to understand that total pressure is dependent on the constituent gas mixtures as stated by Dalton;

Dalton's Law of Partial Pressure states the total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of each individual gas.

This means that each gas has it's own partial pressure, hence the addition of has C cannot affect the partial pressure of A.

Only the total pressure in the vessels would be increased due to the addition of new gas molecules with it's own partial pressure to contribute to the tal pressure of the gas mixture.

The mole fraction of B would also be affected because;

In chemistry, the mole fraction or molar fraction (xi) is defined as the amount of a constituent (expressed in moles), ni divided by the total amount of all constituents in a mixture (also expressed in moles).

Since the total number of moles would change due to addition oof C, then mole fraction of B would also be affected.