Answer:
H2, He, PH3, F2, C5H10
Explanation:
From Graham's law, we understood that lighter gas will diffuse faster than heavier gas under same condition. Graham's law of diffusion states as follow:
The rate (R) of diffusion of a gas is inversely proportional to the square root of its density (D) provided temperature and pressure remains constant. Mathematically, it is represented as:
R & 1/√D
Recall:
Molar Mass (M) = 2 x vapour density (D)
M = 2D
R & 1/√M
From the above, we can see that the rate is inversely proportional to the square root of the molar mass of substance. This implies that lighter gas will diffuse faster.
Now, to rank the above from the highest to rate rate of effusion, let us determine the molecular weight of each substance. This is illustrated below:
Molar Mass of F2 = 19 x 2 = 38g/mol
Molar Mass of He = 4g/mol
Molar Mass of C5H10 = (12X5) + (10X1) = 70g/mol
Molar Mass of H2 = 2x1 = 2g/mol
Molar Mass of PH3 = 31 + (3x1) = 34g/mol
Now, we can rank the substance beginning from the highest to the lowest rate of effusion as follow:
Substance >> Molar Mass >> Rank
H2 >>>>>>>>> 2g/mol >>>>>> 1
He >>>>>>>>> 4g/mol >>>>>> 2
PH3 >>>>>>>> 34g/mol >>>>> 3
F2 >>>>>>>>>> 38g/mol >>>> 4
C5H10 >>>>>> 70g/mol >>>> 5
