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Avogadro’s law and gas density: proportionality with molecular mass For two gases at the same temperature and pressure, state how their densities compare with their molecular masses. Choose the correct relationship.

Q: Avogadro’s law and gas density: proportionality with molecular mass For two gases at the same temperature and pressure, state how their densities compare with their molecular masses. Choose the correct relationship.

Concept At the same T and p, Avogadro’s law implies equal molar volumes. Density ρ is ρ = (mass)/(volume) = (M molar mass)/(molar volume). With constant molar volume, ρ ∝ M. Step ρ1/ρ2 = M1/M2 Final Answer Directly proportional to molecular mass

Difficulty: Easy

Directly proportional to molecular mass
Inversely proportional to molecular mass
Equal to molecular mass
Independent of molecular mass

Correct Answer: Directly proportional to molecular mass

Explanation:

Concept
At the same T and p, Avogadro’s law implies equal molar volumes. Density ρ is ρ = (mass)/(volume) = (M molar mass)/(molar volume). With constant molar volume, ρ ∝ M.

Step
ρ₁/ρ₂ = M₁/M₂

Final Answer
Directly proportional to molecular mass

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