Question 1

Which assumption of the Kinetic Molecular Theory is most responsible for the failure of the Ideal Gas Law at high pressures?

Accepted Answer

Gas particles have negligible volume compared to the container.

Question 2

Which correction does the van der Waals equation introduce to account for the finite size of gas particles?

Accepted Answer

Subtracts $nb$ from the volume: $V_{corrected} = V - nb$

Question 3

A real gas is most likely to deviate from ideal behavior under which conditions?

Accepted Answer

High pressure and low temperature

Question 4

Which of the following gases is most likely to behave ideally: $\mathrm{H_2}$, $\mathrm{Cl_2}$, or $\mathrm{CO_2}$? Why?

Accepted Answer

$\mathrm{H_2}$, because it is small and nonpolar with weak intermolecular forces.

Question 5

Which term in the van der Waals equation accounts for intermolecular attractions?

Accepted Answer

$a\left(\frac{n}{V}\right)^2$

Question 6

Given the van der Waals equation $\left(P + a\left(\frac{n}{V}\right)^2\right)(V - nb) = nRT$, what does the constant $b$ represent?

Accepted Answer

The effective volume occupied by one mole of gas particles

Question 7

Why does the pressure of a real gas become lower than predicted by the Ideal Gas Law at low temperatures?

Accepted Answer

Intermolecular attractions reduce the force of collisions with the container walls.

Question 8

Which gas is more likely to exhibit real gas behavior: $\mathrm{CH_4}$ or $\mathrm{H_2O}$? Why?

Accepted Answer

$\mathrm{H_2O}$, because it has strong intermolecular forces (hydrogen bonding).

Question 9

A sample of $1.00$ mol of $\mathrm{CO_2}$ is confined in a $1.00$ L container at $300.0\ ^\circ\mathrm{C}$. Using the Ideal Gas Law, calculate the pressure. ($R = 0.0821\ \mathrm{L\ atm\ mol^{-1}\ K^{-1}}$)

Accepted Answer

$7.47\ \mathrm{atm}$

Question 10

For the same sample in the previous question, using the van der Waals equation with $a = 3.59\ \mathrm{L^2\ atm\ mol^{-2}}$ and $b = 0.0427\ \mathrm{L\ mol^{-1}}$, what is the corrected pressure?

Accepted Answer

$7.19\ \mathrm{atm}$

Question 11

Why do gases deviate more from ideal behavior at high pressures?

Accepted Answer

The volume of gas particles becomes significant compared to the container volume.

Question 12

Which van der Waals constant is most closely associated with the strength of intermolecular forces?

Accepted Answer

$a$

Question 13

A gas sample behaves more ideally when:

Accepted Answer

The particles are far apart and have weak intermolecular forces.

Question 14

Which of the following best explains why the van der Waals equation is more accurate than the Ideal Gas Law for real gases?

Accepted Answer

It accounts for both the finite volume of gas particles and intermolecular attractions.

Question 15

If a gas has a large value for the van der Waals constant $a$, what does this indicate?

Accepted Answer

The gas has strong intermolecular attractions.

Question 16

Which real-world scenario would most likely require the use of the van der Waals equation instead of the Ideal Gas Law?

Accepted Answer

Calculating the pressure of a gas in a scuba tank at high pressure.

Real Gases and Deviations from Ideal Gas Behavior

Study Guide - Practice Questions

Study Guide - Flashcards