Question

1. equimolar samples of ch4(g) and c2h6(g) are in identical containers at the same temperature. the c2h6(g) deviates much more from ideal behavior than the ch4(g) does. which of the following best helps explain this deviation?

a. c2h6 molecules have more hydrogen bonding than ch4 molecules do.
b. c2h6 molecules have a larger, more polarizable electron cloud than ch4 molecules do.
c. the c2h6 molecules have a greater average kinetic energy than the ch4 molecules have.
d. the c2h6 molecules have a greater average speed than the ch4 molecules have.

1. the gases co2(g) and nh3(g) can be liquefied at 20°c by compressing them to sufficiently high pressures. a student claims that nh3(g) can be liquefied at a lower pressure than co2(g) can be liquefied. which of the following is the best justification for this claim?

a. at 20°c, the average speed of nh3 molecules is greater than that of co2 molecules because nh3 molecules have less mass than co2 molecules have.
b. co2 is a nonpolar molecule that has no significant intermolecular forces, whereas nh3 has strong london dispersion intermolecular forces.
c. both co2 and nh3 are nonpolar molecules that have only london dispersion intermolecular forces, but the larger electron cloud of co2 molecules causes it to have stronger intermolecular forces.
d. co2 is a nonpolar molecule that has london dispersion intermolecular forces that are weaker than the dipole - dipole and london dispersion forces between the polar nh3 molecules.

Explanation:

Question 13:

Hydrogen bonding is not present in either $C_{2}H_{6}$ or $CH_{4}$ as neither has $H$ bonded to $N$, $O$, or $F$. Average kinetic energy and speed are the same for equimolar samples at the same temperature. Larger, more polarizable electron - clouds cause greater deviation from ideal gas behavior. $C_{2}H_{6}$ has a larger electron cloud than $CH_{4}$.

Question 14:

$CO_{2}$ is non - polar with only London dispersion forces. $NH_{3}$ is polar with dipole - dipole and London dispersion forces. Stronger intermolecular forces in $NH_{3}$ mean it can be liquefied at a lower pressure.

Answer:

1. B. $C_{2}H_{6}$ molecules have a larger, more polarizable electron cloud than $CH_{4}$ molecules do.
2. D. $CO_{2}$ is a nonpolar molecule that has London dispersion intermolecular forces that are weaker than the dipole - dipole and London dispersion forces between the polar $NH_{3}$ molecules.