Answer :
Answer: The molar mass of each gas
Explanation:
Mole fraction is the ratio of moles of that component to the total moles of solution. Moles of solute is the ratio of given mass to the molar mass.
[tex]\text{Mole fraction of solute}=\frac{\text{Moles of solute}}{\text{Total Moles}}[/tex]
Suppose if there are three gases A, B and C.
a) [tex]\text{Mole fraction of A}=\frac{\text{Moles of A}}{\text{ Moles of (A+B+C)}}[/tex]
b) [tex]\text{Mole fraction of B}=\frac{\text{Moles of B}}{\text{ Moles of (A+B+C)}}[/tex]
c) [tex]\text{Mole fraction of C}=\frac{\text{Moles of C}}{\text{ Moles of (A+B+C)}}[/tex]
moles of solute =[tex]\frac{\text {given mass}}{\text {Molar mass}}[/tex]
Thus if mass of each gas is known , we must know the molar mass of each gas to know the moles of each gas.