Q: A weather balloon is released at sea level where the atmospheric pressure is $1.00$ atm and the temperature is $20^ \circ$C. As it rises, the pressure drops to $0.60$ atm and the temperature drops to $-10^ \circ$C. If the initial volume of the balloon is $2.0$ L, what is its final volume, assuming the amount of gas remains constant?

$V_2 = V_1 \times \frac{P_1}{P_2} \times \frac{T_2}{T_1} = 2.0\,\mathrm{L} \times \frac{1.00}{0.60} \times \frac{263}{293} = 3.0\,\mathrm{L}$

Q: A sample of gas occupies $4.00$ L at $27^ \circ$C and $1.00$ atm. What will be its volume at $127^ \circ$C and $1.00$ atm?

$V_2 = V_1 \times \frac{T_2}{T_1} = 4.00\,\mathrm{L} \times \frac{400}{300} = 5.33\,\mathrm{L}$

Q: Which of the following is the correct value for standard atmospheric pressure in pascals (Pa)?

$1.01325 \times 10^5\,\mathrm{Pa}$

Q: A $0.50$ mol sample of nitrogen gas is confined in a $12.0$ L container at $25^ \circ$C. What is the pressure exerted by the gas? ($R = 0.0821\,\mathrm{L\cdot atm\cdot mol^{-1}\cdot K^{-1}}$)

$P = \frac{nRT}{V} = \frac{0.50 \times 0.0821 \times 298}{12.0} = 1.02\,\mathrm{atm}$

Q: A sample of methane gas has a volume of $38$ mL at $5^ \circ$C. It is heated to $86^ \circ$C at constant pressure. What is its new volume?

$V_2 = V_1 \times \frac{T_2}{T_1} = 38\,\mathrm{mL} \times \frac{359}{278} = 49\,\mathrm{mL}$

Q: A $0.845$ mol sample of nitrogen gas is at $315$ K and $0.920$ atm. What is the volume of the gas?

$V = \frac{nRT}{P} = \frac{0.845 \times 0.0821 \times 315}{0.920} = 23.8\,\mathrm{L}$

Question 1

A weather balloon is released at sea level where the atmospheric pressure is $1.00$ atm and the temperature is $20^
\circ$C. As it rises, the pressure drops to $0.60$ atm and the temperature drops to $-10^
\circ$C. If the initial volume of the balloon is $2.0$ L, what is its final volume, assuming the amount of gas remains constant?

Accepted Answer

$V_2 = V_1 	imes \frac{P_1}{P_2} 	imes \frac{T_2}{T_1} = 2.0\,\mathrm{L} 	imes \frac{1.00}{0.60} 	imes \frac{263}{293} = 3.0\,\mathrm{L}$

Question 2

Which of the following best describes the relationship between the pressure and volume of a gas at constant temperature, according to Boyle's Law?

Accepted Answer

They are inversely proportional: $P \propto \frac{1}{V}$

Question 3

A sample of gas occupies $4.00$ L at $27^
\circ$C and $1.00$ atm. What will be its volume at $127^
\circ$C and $1.00$ atm?

Accepted Answer

$V_2 = V_1 	imes \frac{T_2}{T_1} = 4.00\,\mathrm{L} 	imes \frac{400}{300} = 5.33\,\mathrm{L}$

Question 4

Which of the following is the correct value for standard atmospheric pressure in pascals (Pa)?

Accepted Answer

$1.01325 	imes 10^5\,\mathrm{Pa}$

Question 5

A $0.50$ mol sample of nitrogen gas is confined in a $12.0$ L container at $25^
\circ$C. What is the pressure exerted by the gas? ($R = 0.0821\,\mathrm{L\cdot atm\cdot mol^{-1}\cdot K^{-1}}$)

Accepted Answer

$P = \frac{nRT}{V} = \frac{0.50 	imes 0.0821 	imes 298}{12.0} = 1.02\,\mathrm{atm}$

Question 6

Which of the following statements about the kinetic molecular theory (KMT) is correct?

Accepted Answer

The average kinetic energy of gas molecules is directly proportional to the absolute temperature.

Question 7

A sample of methane gas has a volume of $38$ mL at $5^
\circ$C. It is heated to $86^
\circ$C at constant pressure. What is its new volume?

Accepted Answer

$V_2 = V_1 	imes \frac{T_2}{T_1} = 38\,\mathrm{mL} 	imes \frac{359}{278} = 49\,\mathrm{mL}$

Question 8

Which of the following is NOT an assumption of the kinetic molecular theory for ideal gases?

Accepted Answer

Gas molecules have significant volume compared to the container.

Question 9

A $0.845$ mol sample of nitrogen gas is at $315$ K and $0.920$ atm. What is the volume of the gas?

Accepted Answer

$V = \frac{nRT}{P} = \frac{0.845 	imes 0.0821 	imes 315}{0.920} = 23.8\,\mathrm{L}$

Question 10

Which of the following best explains why a barometer can be used to measure atmospheric pressure?

Accepted Answer

Atmospheric pressure pushes mercury up the barometer tube until the weight of the mercury column balances the atmospheric force.

Question 11

A $2.00$ L sample of gas at $1.00$ atm and $273$ K contains $0.089$ mol. If the amount of gas is doubled at constant temperature and pressure, what is the new volume?

Accepted Answer

$V_2 = V_1 	imes \frac{n_2}{n_1} = 2.00\,\mathrm{L} 	imes \frac{0.178}{0.089} = 4.00\,\mathrm{L}$

Question 12

Which of the following is the correct value for the universal gas constant $R$ when using pressure in atm and volume in liters?

Accepted Answer

$0.0821\,\mathrm{L\cdot atm\cdot mol^{-1}\cdot K^{-1}}$

Question 13

A $12.2$ L sample of $O_2$ gas at $1.00$ atm and $25^
\circ$C contains $0.50$ mol. If all of this $O_2$ is converted to $O_3$ at the same temperature and pressure, what is the volume of the $O_3$ produced?

Accepted Answer

$0.50\,\mathrm{mol}\,O_2 	imes \frac{2\,\mathrm{mol}\,O_3}{3\,\mathrm{mol}\,O_2} = 0.33\,\mathrm{mol}\,O_3$; $V_2 = V_1 	imes \frac{n_2}{n_1} = 12.2\,\mathrm{L} 	imes \frac{0.33}{0.50} = 8.05\,\mathrm{L}$

Question 14

Which of the following is a real-world example of Dalton's Law of Partial Pressures?

Accepted Answer

The total pressure in a scuba tank is the sum of the partial pressures of oxygen, nitrogen, and other gases.

Question 15

Which of the following best explains why the ideal gas law does not perfectly describe the behavior of real gases at high pressures?

Accepted Answer

At high pressures, the volume of gas molecules and intermolecular forces become significant.

Question 16

A sample of hydrogen gas occupies $8.56$ L at $0^
\circ$C and $1.50$ atm. How many moles of hydrogen are present?

Accepted Answer

$n = \frac{PV}{RT} = \frac{1.50 	imes 8.56}{0.0821 	imes 273} = 0.57\,\mathrm{mol}$

Question 17

Which of the following is the correct conversion between pressure units?

Accepted Answer

$1\,\mathrm{atm} = 760\,\mathrm{mm\,Hg} = 101,325\,\mathrm{Pa}$

Question 18

Which of the following best describes the meaning of temperature in the context of the kinetic molecular theory?

Accepted Answer

Temperature is a measure of the average kinetic energy of the gas molecules.

Gas Laws and Properties: General Chemistry Study Notes

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