Q: A sample of nitrogen gas is contained in a 2.0 L vessel at 1.0 atm and 300 K. If the temperature is increased to 600 K at constant pressure, what will be the new volume of the gas?

$$V_2$$ = $$V_1$$ \times \frac{$$T_2$$}{$$T_1$$} = 2.0\,\mathrm{L} \times \frac{600\,\mathrm{K}}{300\,\mathrm{K}} = 4.0\,\mathrm{L}$$

Q: A balloon filled with helium has a volume of 3.0 L at 1.0 atm. If the pressure is increased to 2.0 atm at constant temperature, what is the new volume?

$$V_2$$ = $$V_1$$ \times \frac{$$P_1$$}{$$P_2$$} = 3.0\,\mathrm{L} \times \frac{1.0}{2.0} = 1.5\,\mathrm{L}$$

Q: A tire has a pressure of 2.50 atm. What is this pressure in mmHg?

$$2.50\,\mathrm{atm} \times 760\,\mathrm{mmHg}/\mathrm{atm} = 1900\,\mathrm{mmHg}$$

Q: A sample of oxygen gas has a volume of 500 mL at 20°C. At what temperature (in Kelvin) will the volume be 750 mL, assuming pressure and moles are constant?

$$T_2$$ = $$T_1$$ \times \frac{$$V_2$$}{$$V_1$$} = (20 + 273)\,\mathrm{K} \times \frac{750}{500} = 293\,\mathrm{K} \times 1.5 = 439.5\,\mathrm{K}$$

Q: A scuba tank contains oxygen at 0.400 atm and helium at 600 mmHg. What is the total pressure in the tank in mmHg?

$$0.400\,\mathrm{atm} \times 760\,\mathrm{mmHg}/\mathrm{atm} = 304\,\mathrm{mmHg}$$; $$304\,\mathrm{mmHg} + 600\,\mathrm{mmHg} = 904\,\mathrm{mmHg}$$

Q: At STP, what volume does 3.00 moles of carbon dioxide gas occupy?

$$3.00\,\mathrm{mol} \times 22.4\,\mathrm{L}/\mathrm{mol} = 67.2\,\mathrm{L}$$

Question 1

According to the kinetic molecular theory, which statement best explains why gases are compressible?

Accepted Answer

Gas particles are very far apart, so there is a lot of empty space between them.

Question 2

A sample of nitrogen gas is contained in a 2.0 L vessel at 1.0 atm and 300 K. If the temperature is increased to 600 K at constant pressure, what will be the new volume of the gas?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$T_2$$}{$$T_1$$} = 2.0\,\mathrm{L} 	imes \frac{600\,\mathrm{K}}{300\,\mathrm{K}} = 4.0\,\mathrm{L}$$

Question 3

Which of the following is NOT a property used to describe a gas?

Accepted Answer

Density ($$d)$$

Question 4

A balloon filled with helium has a volume of 3.0 L at 1.0 atm. If the pressure is increased to 2.0 atm at constant temperature, what is the new volume?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$P_1$$}{$$P_2$$} = 3.0\,\mathrm{L} 	imes \frac{1.0}{2.0} = 1.5\,\mathrm{L}$$

Question 5

Which of the following best describes atmospheric pressure at high altitudes?

Accepted Answer

It decreases as altitude increases.

Question 6

A tire has a pressure of 2.50 atm. What is this pressure in mmHg?

Accepted Answer

$$2.50\,\mathrm{atm} 	imes 760\,\mathrm{mmHg}/\mathrm{atm} = 1900\,\mathrm{mmHg}$$

Question 7

Which law explains why a balloon expands when heated at constant pressure?

Accepted Answer

Charles's Law

Question 8

A sample of oxygen gas has a volume of 500 mL at 20°C. At what temperature (in Kelvin) will the volume be 750 mL, assuming pressure and moles are constant?

Accepted Answer

$$T_2$$ = $$T_1$$ 	imes \frac{$$V_2$$}{$$V_1$$} = (20 + 273)\,\mathrm{K} 	imes \frac{750}{500} = 293\,\mathrm{K} 	imes 1.5 = 439.5\,\mathrm{K}$$

Question 9

Which of the following statements about the Kelvin temperature scale is correct?

Accepted Answer

Kelvin is used because it directly relates to the average kinetic energy of gas particles.

Question 10

A scuba tank contains oxygen at 0.400 atm and helium at 600 mmHg. What is the total pressure in the tank in mmHg?

Accepted Answer

$$0.400\,\mathrm{atm} 	imes 760\,\mathrm{mmHg}/\mathrm{atm} = 304\,\mathrm{mmHg}$$; $$304\,\mathrm{mmHg} + 600\,\mathrm{mmHg} = 904\,\mathrm{mmHg}$$

Question 11

Which law states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each gas?

Accepted Answer

Dalton's Law of Partial Pressures

Question 12

At STP, what volume does 3.00 moles of carbon dioxide gas occupy?

Accepted Answer

$$3.00\,\mathrm{mol} 	imes 22.4\,\mathrm{L}/\mathrm{mol} = 67.2\,\mathrm{L}$$

Question 13

A sample of gas has a pressure of 1.20 atm, a volume of 500 mL, and a temperature of 27°C. What will the pressure be if the volume is decreased to 250 mL and the temperature is increased to 127°C? (Use the combined gas law.)

Accepted Answer

$$P_2$$ = $$P_1$$ 	imes \frac{$$V_1$$}{$$V_2$$} 	imes \frac{$$T_2$$}{$$T_1$$} = 1.20\,\mathrm{atm} 	imes \frac{500}{250} 	imes \frac{400}{300} = 1.20 	imes 2 	imes 1.333 = 3.20\,\mathrm{atm}$$

Question 14

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

Accepted Answer

Pressure and volume are inversely proportional.

Question 15

A 1.0 L sample of gas contains 0.50 moles. If the amount of gas is increased to 1.00 mole at constant temperature and pressure, what is the new volume?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$n_2$$}{$$n_1$$} = 1.0\,\mathrm{L} 	imes \frac{1.00}{0.50} = 2.0\,\mathrm{L}$$

Question 16

During inhalation, what happens to the pressure inside the lungs according to Boyle's Law?

Accepted Answer

Pressure decreases and air flows in.

Question 17

A gas sample at 1.00 atm and 273 K occupies 22.4 L. If the pressure is doubled and the temperature is halved, what is the new volume?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$P_1$$}{$$P_2$$} 	imes \frac{$$T_2$$}{$$T_1$$} = 22.4\,\mathrm{L} 	imes \frac{1.00}{2.00} 	imes \frac{136.5}{273} = 22.4 	imes 0.5 	imes 0.5 = 5.6\,\mathrm{L}$$

Question 18

Which of the following is a correct conversion for standard atmospheric pressure?

Accepted Answer

$$1\,\mathrm{atm} = 760\,\mathrm{mmHg} = 760\,\mathrm{Torr}$$

Chapter 8: Gases – Properties and Behavior (General Chemistry Study Notes)

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