Q: A 2.00 L container holds 0.50 mol of O2 and 1.00 mol of N2 at 298 K. What is the total pressure in the container? (Use $$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

$$P = \frac{(0.50 + 1.00) \times 0.0821 \times 298}{2.00} = 2.0\ \mathrm{atm}$$

Question 1

Which of the following best explains why water has a much higher boiling point than expected based on its molecular weight?

Accepted Answer

Water molecules form strong hydrogen bonds due to the presence of highly electronegative oxygen atoms bonded to hydrogen.

Question 2

Which of the following statements about dispersion forces is correct?

Accepted Answer

Dispersion forces increase with increasing molecular size and number of electrons.

Question 3

A sample of helium gas is held at constant temperature inside a cylinder with a movable piston. If the external pressure is doubled, what happens to the volume of the gas?

Accepted Answer

The volume is halved.

Question 4

Which of the following molecules can form hydrogen bonds with another molecule of the same substance?

Accepted Answer

NH3

Question 5

A 2.00 L container holds 0.50 mol of O2 and 1.00 mol of N2 at 298 K. What is the total pressure in the container? (Use $$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$P = \frac{(0.50 + 1.00) 	imes 0.0821 	imes 298}{2.00} = 2.0\ \mathrm{atm}$$

Question 6

Which of the following best describes the difference between intermolecular and intramolecular forces?

Accepted Answer

Intermolecular forces are generally much weaker than intramolecular forces.

Question 7

Which of the following gases will have the highest density at the same temperature and pressure?

Accepted Answer

Chlorine ($$Cl_2)$$

Question 8

A hot air balloon rises because the density of the air inside the balloon is lower than the density of the surrounding air. Which equation relates the density of a gas to its molar mass, pressure, and temperature?

Accepted Answer

$$\rho = \frac{MP}{RT}$$

Question 9

Which of the following is a consequence of hydrogen bonding in water?

Accepted Answer

Water has a high boiling point compared to other group 16 hydrides.

Question 10

Which of the following best explains why the boiling points of noble gases increase down the group?

Accepted Answer

The number of electrons increases, enhancing dispersion forces.

Question 11

A 1.00 L flask contains 0.50 mol of $$N_2$$ and 0.50 mol of $$O_2 at 298 K. $$What is the mole fraction of $$O_2 in $$the mixture?

Accepted Answer

$$0.50$$

Question 12

Which of the following statements about the kinetic molecular theory of gases is FALSE?

Accepted Answer

Gas particles attract each other strongly at all times.

Question 13

Which of the following best describes the relationship between the volume and temperature of a gas at constant pressure?

Accepted Answer

The volume of a gas is directly proportional to its temperature in Kelvin.

Question 14

Which of the following is NOT a type of intermolecular force?

Accepted Answer

Ionic bonding

Question 15

A gas mixture contains 2.0 mol of $$N_2$$, 1.0 mol of $$O_2$$, and 1.0 mol of $$CO_2. If $$the total pressure is 4.0 atm, what is the partial pressure of $$O_2$$?

Accepted Answer

$$1.0\ \mathrm{atm}$$

Question 16

Which of the following best explains why methane ($$CH_4) $$cannot form hydrogen bonds?

Accepted Answer

Methane does not contain a highly electronegative atom bonded to hydrogen.

Question 17

Which of the following equations is the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 18

Which of the following is a real-world application of surface tension in water?

Accepted Answer

The ability of insects to walk on water surfaces.

Question 19

Which of the following best describes the effect of increasing temperature on the density of a gas at constant pressure?

Accepted Answer

The density decreases.

States of Matter and Gas Laws: Structure, Properties, and Calculations

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