3.6 Deviation from the Ideal Gas Law

Multiple Choice

Ar (g)
Ar (g) deviates more from ideal behavior at extremely high pressures than Ne (g) does. Which of the following is one reason for this difference?

• The particle volume of Ar is greater than Ne

• Ar atoms have more valence electrons than Ne atoms have, so Ar atoms have greater interparticle forces.

• The intermolecular forces between Ne atoms are greater than those between Ar atoms.

• Ar atoms are more attracted to the walls of the container than Ne atoms are.

Multiple Choice

The diagrams represent two samples of Xe gas in containers of equal volume at 280K. Which of the following correctly compares the two samples in terms of their deviation from ideal gas behavior and explains why?

• The gas in sample 1 would deviate more from ideal behavior because the average distance an Xe atom travels before colliding with another Xe atom is greater.

• The gas in sample 2 would deviate more from ideal behavior because the Xe atoms are closer together, leading to an increase in intermolecular attractions.

• The gas in sample 2 would deviate more from ideal behavior because the average speed of the Xe atoms is less, leading to an increase in intermolecular attractions.

• The gases in both sample 1 and sample 2 would show the same deviation from ideal behavior.

Multiple Choice

Which of the following best helps explain why the pressure of a sample of CH₄ (g) (molar mass 16g/mol) is closer to the pressure predicted by the ideal gas law than a sample of NH₃ (g) (molar mass 17g/mol) ?

• 
  NH₃ molecules are polar while CH₄ molecules are not, and the greater attractions between NH₃ molecules cause the molecules to collide with the walls of the container with less force.

• 
  NH₃ molecules have a greater molar mass than CH₄ molecules, so the NH₃ molecules collide with the walls of the container with more force.

• CH₄ molecules have more hydrogen atoms than NH₃ molecules, so CH₄ molecules have more hydrogen bonding and greater intermolecular forces.

• CH₄ molecules are larger than NH₃ molecules, so the actual CH₄ molecules take up a significant portion of the volume of the gas.