Q: A sample of gas occupies 8.0 L at 2.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what will be the new volume?

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{2.0 \times 8.0}{4.0} = 4.0\ \text{L}$$

Q: A 1600 g pot of water is heated from $$25\ ^\circ\text{C} to$$ $$100\ ^\circ\text{C}. $$How many calories are needed? (Specific heat of water = $$1.00\ \text{cal}/(\text{g}\ ^\circ\text{C}))$$

$$\text{heat} = 1600 \times 75 \times 1.00 = 1.2 \times 10^5$\ \text{cal}$$

Q: A sample of exhaled air contains the following partial pressures: $$N_2 (563 mm Hg$$), $$O_2 (118 mm Hg$$), $$CO_2 (30 mm Hg$$), and $$H_2O (50 mm Hg). $$What is the total pressure?

$$P_{\text{total}} = 563 + 118 + 30 + 50 = 761\ \text{mm Hg}$$

Q: If 2.0 L of $$N_2$$ gas at STP is given, how many moles of $$N_2$$ are present?

$$n = \frac{2.0}{22.4} = 0.089\ \text{mol}$$

Question 1

Which of the following statements best explains why gases are compressible, but solids are not?

Accepted Answer

Gas particles are randomly arranged and far apart, allowing them to be compressed.

Question 2

A sample of gas occupies 8.0 L at 2.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what will be the new volume?

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{2.0 	imes 8.0}{4.0} = 4.0\ 	ext{L}$$

Question 3

Which process is exothermic?

Accepted Answer

Condensation

Question 4

A weather balloon contains 233 L of helium at $$22\ ^\circ	ext{C}$$ and 760 mm Hg. What is the volume of the balloon when it ascends to an altitude where the temperature is $$-54\ ^\circ	ext{C}$$ and 511 mm Hg? (Use the combined gas law.)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$ $$T_2$$}{$$T_1$$ $$P_2$$} = \frac{760 	imes 233 	imes 219}{295 	imes 511} = 116\ 	ext{L}$$

Question 5

Which of the following molecules can exhibit hydrogen bonding interactions?

Accepted Answer

NH$$_3$$

Question 6

Which of the following best describes the relationship between intermolecular forces and boiling point?

Accepted Answer

The stronger the intermolecular forces, the higher the boiling point.

Question 7

A 1600 g pot of water is heated from $$25\ ^\circ	ext{C} to$$ $$100\ ^\circ	ext{C}. $$How many calories are needed? (Specific heat of water = $$1.00\ 	ext{cal}/(	ext{g}\ ^\circ	ext{C}))$$

Accepted Answer

$$	ext{heat} = 1600 	imes 75 	imes 1.00 = 1.2 	imes 10^5$\ 	ext{cal}$$

Question 8

Which of the following is true about crystalline and amorphous solids?

Accepted Answer

Crystalline solids have a regular arrangement of particles, while amorphous solids do not.

Question 9

Which of the following best explains why water has a higher surface tension than methane?

Accepted Answer

Water forms hydrogen bonds, which are stronger than the London dispersion forces in methane.

Question 10

A sample of exhaled air contains the following partial pressures: $$N_2 (563 mm Hg$$), $$O_2 (118 mm Hg$$), $$CO_2 (30 mm Hg$$), and $$H_2O (50 mm Hg). $$What is the total pressure?

Accepted Answer

$$P_{	ext{total}} = 563 + 118 + 30 + 50 = 761\ 	ext{mm Hg}$$

Question 11

Which of the following is the correct expression for the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 12

Which of the following processes is endothermic?

Accepted Answer

Sublimation

Question 13

If 2.0 L of $$N_2$$ gas at STP is given, how many moles of $$N_2$$ are present?

Accepted Answer

$$n = \frac{2.0}{22.4} = 0.089\ 	ext{mol}$$

Question 14

Which of the following best describes the effect of increasing temperature on the vapor pressure of a liquid?

Accepted Answer

Vapor pressure increases as temperature increases.

Question 15

Which of the following is NOT a type of crystalline solid?

Accepted Answer

Amorphous solid

Question 16

A human breathes in 0.50 L of air at 1.0 atm and 37$$^\circC. $$How many moles of air are inhaled? ($$R = 0.08206\ 	ext{L atm}/	ext{mol K})$$

Accepted Answer

$$n = \frac{PV}{RT} = \frac{1.0 	imes 0.50}{0.08206 	imes 310} = 0.020\ 	ext{mol}$$

Question 17

Which of the following best describes the effect of increasing the number of moles of gas in a fixed container at constant temperature and pressure?

Accepted Answer

The volume increases.

Chapter 7: Gases, Liquids, and Solids – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard