A container at room temperature is filled with equal moles of O2(g), NO2(g) and He(g). The gases slowly leak through a pinhole in the container. After some gas has effused, which relationship is true about the partial pressures of the gas remaining in the container?
a) P He < P O2 < P NO2
b) P NO2 < P O2 < P He
c) P O2 < P NO2 < P He
d) P O2 = P NO2 = P He
I would assume since they have the same molar values they would technically have the same pressure assuming they are in the same container. However, I am not 100% sure.
But does each gas effuse at the same rate?
I am not sure.
They don't. Look up Graham's Law. The rate of effusion is inverse;u proportional to the square root of the molar mass.
To determine the relationship between the partial pressures of the remaining gases, we need to consider Graham's Law of Effusion. Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass.
In this case, since the moles of O2, NO2, and He are equal, their molar masses can be compared directly. The molar mass of O2 is approximately 32 g/mol, the molar mass of NO2 is approximately 46 g/mol, and the molar mass of He is approximately 4 g/mol.
From Graham's Law, we can infer that the gas with the lowest molar mass will effuse faster than the others. As the gases slowly leak through the pinhole, the gas with the lowest molar mass, He, will effuse more rapidly compared to O2 and NO2.
This preferential effusion of He will result in a decrease in its partial pressure in the container compared to O2 and NO2. Therefore, the relationship between the partial pressures of the remaining gases in the container will be:
a) P He < P O2 < P NO2
So, option (a) is the correct answer.