Q: A pilot undergoes altitude training. He starts his training at an atmospheric pressure of 762 mmHg, where his lungs hold 6.00 L of air. He changes altitude, and his lungs expand to hold 6.25 L of air. What is the new atmospheric pressure in mmHg? (Assume temperature and amount of gas are constant.)

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{762 \times 6.00}{6.25} = 731\ \text{mmHg}$$

Q: A child's balloon containing 8.5 L of helium gas at sea level (760 mmHg) is released and floats away. What will the volume of the helium be when the balloon rises to the point where the atmospheric pressure is 380 mmHg? (Assume temperature and amount of gas are constant.)

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{760 \times 8.5}{380} = 17\ \text{L}$$

Q: A sample of gas is compressed from 10.0 L to 2.0 L at constant temperature. If the initial pressure was 200 mmHg, what is the final pressure?

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{200 \times 10.0}{2.0} = 1000\ \text{mmHg}$$

Question 1

A pilot undergoes altitude training. He starts his training at an atmospheric pressure of 762 mmHg, where his lungs hold 6.00 L of air. He changes altitude, and his lungs expand to hold 6.25 L of air. What is the new atmospheric pressure in mmHg? (Assume temperature and amount of gas are constant.)

Accepted Answer

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{762 	imes 6.00}{6.25} = 731\ 	ext{mmHg}$$

Question 2

A child's balloon containing 8.5 L of helium gas at sea level (760 mmHg) is released and floats away. What will the volume of the helium be when the balloon rises to the point where the atmospheric pressure is 380 mmHg? (Assume temperature and amount of gas are constant.)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{760 	imes 8.5}{380} = 17\ 	ext{L}$$

Question 3

Which change of state is occurring when ice forms on a puddle of water during the winter?

Accepted Answer

Freezing

Question 4

What is the change of state called when dew forms on grass in the morning?

Accepted Answer

Condensation

Question 5

What is the change of state called when water boils?

Accepted Answer

Vaporization

Question 6

Rank the following intermolecular forces from weakest to strongest: London forces, dipole-dipole, hydrogen bonding, ion-dipole, ionic attraction.

Accepted Answer

London forces \u003c dipole-dipole \u003c hydrogen bonding \u003c ion-dipole \u003c ionic attraction

Question 7

Which type of intermolecular force is present in all molecules, regardless of polarity?

Accepted Answer

London dispersion forces

Question 8

Which of the following molecules can form hydrogen bonds with water? (Select all that apply.)
A. $$\mathrm{CH_3CH_2NHCH_2CH_3}
B$$. $$\mathrm{CH_3CH_2Cl}
C$$. $$\mathrm{CH_3CN}$$

Accepted Answer

A and C only

Question 9

Given the structure of isopropanol ($$\mathrm{CH_3CH(OH)CH_3$}$$), how many hydrogen bonds can it form with water molecules?

Accepted Answer

It can form up to 3 hydrogen bonds: 1 as a donor (from the OH hydrogen) and 2 as an acceptor (from the lone pairs on the oxygen).

Question 10

Which of the following best describes a hydrogen-bond donor?

Accepted Answer

A molecule with a hydrogen atom covalently bonded to an oxygen, nitrogen, or fluorine (O, N, or F)

Question 11

Which of the following substances exhibits the strongest intermolecular force in its pure form?
A. Diethyl ether ($$\mathrm{CH_3CH_2OCH_2CH_3})
B. $$Isopropanol ($$\mathrm{CH_3CH(OH)CH_3$})
C. $$Trichloroethane ($$\mathrm{CCl_3CH_3})$$

Accepted Answer

B. Isopropanol ($$\mathrm{CH_3CH(OH)CH_3$}) $$due to hydrogen bonding

Question 12

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) $$dissolves readily in water?

Accepted Answer

Ion-dipole interactions between the $$\mathrm{Na^+}$$ and $$\mathrm{Cl^-}$$ ions and the polar water molecules

Question 13

A plastic wrap clings to itself and to other surfaces due to which type of intermolecular force?

Accepted Answer

London dispersion forces

Question 14

Which of the following statements about dipole-dipole interactions is correct?

Accepted Answer

They occur between molecules that have permanent dipoles (polar molecules).

Question 15

Which of the following changes of state is an example of deposition?

Accepted Answer

Frost forming from water vapor on a cold surface

Question 16

A sample of gas is compressed from 10.0 L to 2.0 L at constant temperature. If the initial pressure was 200 mmHg, what is the final pressure?

Accepted Answer

$$P_2$$ = \frac{$$P_1$$ $$V_1$$}{$$V_2$$} = \frac{200 	imes 10.0}{2.0} = 1000\ 	ext{mmHg}$$

Question 17

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changing directly to a gas without passing through the liquid state

Question 18

Which of the following molecules would have the highest boiling point, assuming similar molar masses?

Accepted Answer

A molecule capable of hydrogen bonding

Practice Problems: Gas Laws, Changes of State, and Intermolecular Forces

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