Ideal Behavior

Under what conditions do real gases behave most like an ideal gas?

• Low temperature and low pressure

• Low temperature and high pressure

• High temperature and low pressure

• High temperature and high pressure

What gases deviate most from ideal behavior?

• polar molecules with small molar masses

• polar molecules with large molar masses

• nonpolar molecules with small molar masses

• nonpolar molecules with large molar masses

At 400 K both compounds are gases. At this temperature, which compound, CH₄(g) or CCl₄(g), behaves more like an ideal gas?

• CH₄(g)

• CCl₄(g)

Which of the following behaves most like an ideal gas at the conditions indicated?

• H₂(g) molecules at 10^-3 atm and 200°C

• O₂(g) molecules at 20 atm and 200°C

• SO₂(g) molecules at 20 atm and 200°C

• NH₃(g) molecules at 20 atm and 200°C

• NH₃(g) molecules at 20 atm and 300°C

The table below contains information about samples of four different gases at 273 K. The samples are in four identical rigid containers numbered 1 through 4.

The best explanation for the lower pressure in container 4 is that SO₂ molecules

• have a larger average speed than the other three gases

• occupy a larger portion of the container volume than the other three gases

• have stronger intermolecular attractions than the other three gases

• contain 𝜋 bonds, while the other gases contain σ only bonds

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 that of Ne.

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

Under which of the following conditions of temperature and pressure will H₂ gas be expected to behave most like an ideal gas?

• 50 K and 0.10 atm

• 50 K and 5.0 atm

• 500 K and 0.10 atm

• 500 K and 50 atm

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

The diagrams above represent two samples of Xe gas in containers of equal volume at 280 K. 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.