Graham's law of effusion
At the same temperature, how does the effusion rate of H2 (2 g/mol) compare with that of O2 (32 g/mol)?
Answer C: explanation for every choice
A
This inverts the ratio. The lighter gas effuses faster.
B
Both gases have the same average kinetic energy, but the lighter molecules move faster.
C
Correct. Rate ∝ 1/√M, so rateH₂/rateO₂ = √(32/2) = 4.
D
This forgets the square root.
TakeawayEffusion rate ∝ 1/√(molar mass).
Equation usedGraham's law of effusion
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