Question

Equal masses of 3 ideal gases x, y, z are mixed in a sealed rigid container. If the temperature of the system remains constant, which of the following statements about the partial pressure of gas X is correct?
A) It is equal to 1 / 3 the total pressure
B) It depends upon the intermolecular forces of attraction between molecules of X, Y and Z.
C) It depends on the relative molecular masses of X, Y and Z.
D) it depends on the average distance traveled between the molecular collisions

Answer 1

Answer:

C)  It depends on the relative molecular masses of X, Y and Z.

Explanation:

Dalton´s law for the partial pressure of an ideal  gas in a mixture is given by the relationship :

Pa =  Xa Ptotal,

where Xa is the mole fraction of gas A times the total pressure  ( Pa + Pb + Pc...)

The mole fraction is, in turn, given by

Xa = mol A / total # moles

Since the moles of a substance  is the mass divided by its molecular weight , it follows that answer C)  is the correct one.