Question

Place the following gases in order of increasing speed at the same temperature. N2, H2, Cl2, CO2, Ar (Please explain)

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Answer 1

The order of increasing speed is: Cl₂ < CO₂ < Ar < N₂ < H₂.

Step-by-step explanation:

• Thomas Graham found that, at a constant temperature and pressure the rates of effusion of various gases are inversely proportional to the square root of their masses.

∨ ∝ 1/√M.

where, ∨ is the rate of diffusion of the gas.

M is the molar mass of the gas.

• Knowing that:

Molar mass of N₂ = 28.0 g/mol.

Molar mass of H₂ = 2.0 g/mol.

Molar mass of Cl₂ = 70.9 g/mol.

Molar mass of CO₂ = 44.0 g/mol.

Molar mass of Ar = 39.94 g/mol.

∵ Molar mass of Cl₂ > Molar mass of CO₂ > Molar mass of Ar > Molar mass of N₂ > Molar mass of H₂.

Remember that ∨ ∝ 1/√M.

∴ The speed of H₂ > N₂ > Ar > CO₂ > Cl₂.

So, the order of increasing speed is: Cl₂ < CO₂ < Ar < N₂ < H₂.