Question

A flask at room temperature contains exactly equal amounts (moles of nitrogen and oxygen.

Answer 1

Equal amounts (moles of nitrogen and oxygen).

a. which gas has the higher partial pressure?

Partial pressure is proportional to the molar fraction of the gas.

Given that there are equal amounts, the molar fractions and the partial pressures are equal.

b. molecules of which gas have the higher average velocity?

The average velocity is inversely related to the square root of molar mass of the gas, then the gass with the lower molar mass will have the higher average velocity.

Molar mass of N2 = 2 * 14 g/mol = 28 g/mol
Molar mass of O2 = 2 * 16 g/mol = 32 g/mol

Then, N2 will have a higher average velocity.


c. the molecules of which gas effuses more quickly if a small hole was opened in the flask?

The effusion rate is inversely related to the square root of the molar mass, then the gas with the lower molar mass will effuse more quickly.

Therefore, N2 will effuse more quickly.