# Quiz 2 - Properties of Gases | Properties of Gases

1

What is the volume occupied by 2 moles of an ideal gas at STP (Standard Temperature and Pressure)?

At STP, one mole of an ideal gas occupies 22.4 L. Therefore, 2 moles will occupy 2×22.42 \times 22.42×22.4 L = 44.8 L.

2

According to Boyle's Law, which of the following statements is true?

Boyle's Law states that the pressure of a gas is inversely proportional to its volume when temperature is held constant (P ∝ ​).

3

Which of the following statements about gases is correct?

Gases take the shape and volume of their container, meaning they have indefinite shape and indefinite volume.

4

Which of the following statements is consistent with the Kinetic Molecular Theory of gases?

The Kinetic Molecular Theory states that gas particles are in constant, random motion and that they have elastic collisions with each other and the walls of the container.

5

What is the pressure of a gas if 0.5 moles of the gas occupy 10 liters at a temperature of 300 K? (Use R = 0.0821 L.atm.K-1.mol−1)

Use the Ideal Gas Law PV = nRT

P = $\frac{\mathrm{nRT}}{\mathrm{V}}$ =  = 1.23 atm

6

If the partial pressures of nitrogen, oxygen, and argon in a container are 500 torr, 200 torr, and 100 torr respectively, what is the total pressure in the container?

According to Dalton's Law of Partial Pressures, the total pressure is the sum of the partial pressures of all gases:
Ptotal = PN2 + PO2 + PAr = 500 torr + 200 torr + 100 torr = 800 torr

7

What is the rate of effusion of helium gas compared to nitrogen gas, given that the molar mass of helium is 4 g/mol and nitrogen is 28 g/mol?

According to Graham's Law of Effusion, the rate of effusion is inversely proportional to the square root of the molar mass:

$\frac{{\mathrm{rate}}_{\mathrm{He}}}{{\mathrm{rate}}_{{\mathrm{N}}_{2}}}$ = $\sqrt{\frac{{\mathrm{M}}_{{\mathrm{N}}_{2}}}{{\mathrm{M}}_{\mathrm{He}}}}$ =

8

A gas mixture contains 3 moles of oxygen (O2​) and 2 moles of nitrogen (N2). What is the mole fraction of nitrogen in the mixture?

The mole fraction is calculated as:

XN2 =  =  =0.4

9

Which of the following gases would you expect to deviate most from ideal behavior at high pressures?

Ammonia has strong intermolecular hydrogen bonding, causing it to deviate more from ideal behavior compared to the other gases listed.

10

A sample of gas is compressed from 4.0 L to 2.0 L at constant temperature. If the initial pressure was 1.0 atm, what is the final pressure?

According to Boyle's Law (P1V1 = P2V2​), if the volume is halved, the pressure will double:

P2 = $\frac{{\mathrm{P}}_{1}{\mathrm{V}}_{1}}{{\mathrm{V}}_{2}}$ =  = 2.0 atm