Q: Given two gases, $$A$$ and $$B$$, at the same temperature, which equation correctly relates their rates of effusion according to Graham's Law?

$$ \frac{\text{Rate}_A}{\text{Rate}_B} = \sqrt{\frac{M_B}{M_A}} $$

Question 1

According to the Kinetic Molecular Theory, which of the following statements is NOT an assumption made about ideal gases?

Accepted Answer

Gas particles experience significant attractive and repulsive forces between each other.

Question 2

Which equation correctly expresses the average kinetic energy of a gas particle according to the Kinetic Molecular Theory?

Accepted Answer

$$ KE = \frac{3}{2}kT $$

Question 3

A balloon filled with helium is released into the atmosphere. As it rises and the temperature decreases, what happens to the average kinetic energy of the helium atoms?

Accepted Answer

It decreases because kinetic energy is directly proportional to temperature.

Question 4

Graham's Law of Effusion can be derived from which fundamental principle of the Kinetic Molecular Theory?

Accepted Answer

The average kinetic energy of gas particles is proportional to temperature.

Question 5

Which of the following gases will effuse the fastest under identical conditions, according to Graham's Law?

Accepted Answer

Hydrogen ($$H_2)$$

Question 6

If the temperature of a gas is doubled (in Kelvin), what happens to the root mean square speed ($$v_{rms}) of $$its particles?

Accepted Answer

$$v_{rms}$$ increases by a factor of $$\sqrt{2}$$

Question 7

A sample contains equal moles of $$H_2$$ and $$O_2 at $$the same temperature. Which statement is true about their average kinetic energies and velocities?

Accepted Answer

Both gases have the same average kinetic energy, but $$H_2$$ molecules move faster.

Question 8

Which of the following best explains why a balloon shrinks when placed in a cold environment, according to the Kinetic Molecular Theory?

Accepted Answer

Gas particles move slower, causing fewer and less forceful collisions with the balloon walls.

Question 9

Given two gases, $$A$$ and $$B$$, at the same temperature, which equation correctly relates their rates of effusion according to Graham's Law?

Accepted Answer

$$ \frac{	ext{Rate}_A}{	ext{Rate}_B} = \sqrt{\frac{M_B}{M_A}} $$

Question 10

Which real-world scenario best illustrates the concept of effusion?

Accepted Answer

A helium balloon slowly deflating over several days.

Question 11

If the molar mass of gas $$A is 4 g/$$mol and gas $$B is 36 g/$$mol, what is the ratio of their rates of effusion ($$\frac{	ext{Rate}_A}{	ext{Rate}_B}$$)?

Accepted Answer

$$ \sqrt{\frac{36}{4}} = 3 $$

Question 12

Which of the following changes would NOT increase the average speed of gas particles in a container?

Accepted Answer

Increasing the pressure at constant temperature.

Question 13

A rigid container holds a sample of gas at constant volume. If the temperature is decreased, what happens to the pressure inside the container?

Accepted Answer

The pressure decreases because particles collide less frequently and with less force.

Question 14

Which of the following is a direct consequence of the assumption that gas particles do not attract or repel each other?

Accepted Answer

Gases expand to fill their containers.

Question 15

If two different gases are at the same temperature, which property must be the same for both according to the Kinetic Molecular Theory?

Accepted Answer

Average kinetic energy per molecule

Kinetic Molecular Theory, Graham’s Law of Effusion, and Gas Particle Velocities

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