Q: A patient with COPD uses an oxygen tank with a pressure of 3800 mmHg and a volume of 12 L. If the oxygen is released until the pressure drops to 570 mmHg (with temperature and amount of gas constant), what is the final volume of the oxygen gas? Use Boyle’s law.

$$V_2 = 12$$\ \mathrm{L} \times \frac{3800\ \mathrm{mmHg}}{570\ \mathrm{mmHg}} = 80\ \mathrm{L}$$

Q: A weather balloon is filled with 15.0 L of helium at 25 °C and 685 mmHg. What is the pressure in mmHg when the balloon rises to a region where the temperature is -35 °C and the volume is 34.0 L? (Assume the amount of gas does not change.)

$$P_2 = 685$$\ \mathrm{mmHg} \times \frac{15.0\ \mathrm{L}}{34.0\ \mathrm{L}} \times \frac{238\ \mathrm{K}}{298\ \mathrm{K}} = 241\ \mathrm{mmHg}$$

Q: A hospital oxygen tank is stored at 120 atm and 25 °C. If a fire raises the temperature to 402 °C, what will the new pressure be, assuming the volume and amount of gas do not change? Will the tank rupture if its safety limit is 180 atm?

$$P_2 = 120$$\ \mathrm{atm} \times \frac{675\ \mathrm{K}}{298\ \mathrm{K}} = 270\ \mathrm{atm}$$; Yes, it will rupture.

Q: A 25.0-mL bubble is released from a diver’s tank at 4.00 atm and 11 °C. What is the volume of the bubble at the surface, where the pressure is 1.00 atm and the temperature is 18 °C? (Assume the amount of gas does not change.)

$$V_2 = 25.0$$\ \mathrm{mL} \times \frac{4.00\ \mathrm{atm}}{1.00\ \mathrm{atm}} \times \frac{291\ \mathrm{K}}{284\ \mathrm{K}} = 102\ \mathrm{mL}$$

Q: A weather balloon contains 44 L of helium at 2.0 moles. If more helium is added to make a total of 5.0 moles (with pressure and temperature constant), what is the final volume?

$$V_2 = 44$$\ \mathrm{L} \times \frac{5.0}{2.0} = 110\ \mathrm{L}$$

Q: What is the volume, in liters, of 64.0 g of $$O_2$$ gas at STP?

$$64.0\ \mathrm{g}\ O_2$ \times \frac{1\ \mathrm{mol}}{32.00\ \mathrm{g}} \times \frac{22.4\ \mathrm{L}}{1\ \mathrm{mol}} = 44.8\ \mathrm{L}$$

Q: A mountain climber inhales air at $$-8\ ^\circ\mathrm{C}$$, and the final volume in the lungs is 569 mL at $$37\ ^\circ\mathrm{C}. $$What was the initial volume of air inhaled, assuming constant pressure and amount of gas?

$$V_1 = 569$$\ \mathrm{mL} \times \frac{265\ \mathrm{K}}{310\ \mathrm{K}} = 486\ \mathrm{mL}$$

Q: A tank of nitrous oxide ($$N_2O) $$has a pressure of 48 psi. What is this pressure in atmospheres? (1 atm = 14.7 psi)

$$48\ \mathrm{psi} \times \frac{1\ \mathrm{atm}}{14.7\ \mathrm{psi}} = 3.3\ \mathrm{atm}$$

Q: A sample contains 8.00 g of $$O_2$$ gas with a volume of 5.00 L. If 4.00 g of $$O_2 is $$added (at constant T and P), what is the new volume?

$$V_2 = 5.00$$\ \mathrm{L} \times \frac{12.00\ \mathrm{g}}{8.00\ \mathrm{g}} = 7.50\ \mathrm{L}$$

Question 1

A patient with COPD uses an oxygen tank with a pressure of 3800 mmHg and a volume of 12 L. If the oxygen is released until the pressure drops to 570 mmHg (with temperature and amount of gas constant), what is the final volume of the oxygen gas? Use Boyle’s law.

Accepted Answer

$$V_2 = 12$$\ \mathrm{L} 	imes \frac{3800\ \mathrm{mmHg}}{570\ \mathrm{mmHg}} = 80\ \mathrm{L}$$

Question 2

Which property of a gas is directly related to the kinetic energy of its particles?

Accepted Answer

Temperature

Question 3

A weather balloon is filled with 15.0 L of helium at 25 °C and 685 mmHg. What is the pressure in mmHg when the balloon rises to a region where the temperature is -35 °C and the volume is 34.0 L? (Assume the amount of gas does not change.)

Accepted Answer

$$P_2 = 685$$\ \mathrm{mmHg} 	imes \frac{15.0\ \mathrm{L}}{34.0\ \mathrm{L}} 	imes \frac{238\ \mathrm{K}}{298\ \mathrm{K}} = 241\ \mathrm{mmHg}$$

Question 4

A hospital oxygen tank is stored at 120 atm and 25 °C. If a fire raises the temperature to 402 °C, what will the new pressure be, assuming the volume and amount of gas do not change? Will the tank rupture if its safety limit is 180 atm?

Accepted Answer

$$P_2 = 120$$\ \mathrm{atm} 	imes \frac{675\ \mathrm{K}}{298\ \mathrm{K}} = 270\ \mathrm{atm}$$; Yes, it will rupture.

Question 5

A 25.0-mL bubble is released from a diver’s tank at 4.00 atm and 11 °C. What is the volume of the bubble at the surface, where the pressure is 1.00 atm and the temperature is 18 °C? (Assume the amount of gas does not change.)

Accepted Answer

$$V_2 = 25.0$$\ \mathrm{mL} 	imes \frac{4.00\ \mathrm{atm}}{1.00\ \mathrm{atm}} 	imes \frac{291\ \mathrm{K}}{284\ \mathrm{K}} = 102\ \mathrm{mL}$$

Question 6

A weather balloon contains 44 L of helium at 2.0 moles. If more helium is added to make a total of 5.0 moles (with pressure and temperature constant), what is the final volume?

Accepted Answer

$$V_2 = 44$$\ \mathrm{L} 	imes \frac{5.0}{2.0} = 110\ \mathrm{L}$$

Question 7

What is the volume, in liters, of 64.0 g of $$O_2$$ gas at STP?

Accepted Answer

$$64.0\ \mathrm{g}\ O_2$ 	imes \frac{1\ \mathrm{mol}}{32.00\ \mathrm{g}} 	imes \frac{22.4\ \mathrm{L}}{1\ \mathrm{mol}} = 44.8\ \mathrm{L}$$

Question 8

A heliox breathing mixture has a total pressure of 7.00 atm. If the partial pressure of $$O_2 is 1140 $$mmHg, what is the partial pressure of He in atm? (1 atm = 760 mmHg)

Accepted Answer

$$P_{He} = 7.00\ \mathrm{atm} - \frac{1140\ \mathrm{mmHg}}{760\ \mathrm{mmHg/atm}} = 7.00\ \mathrm{atm} - 1.50\ \mathrm{atm} = 5.50\ \mathrm{atm}$$

Question 9

Which law explains why a balloon expands when heated, assuming pressure is constant?

Accepted Answer

Charles’s Law

Question 10

A mountain climber inhales air at $$-8\ ^\circ\mathrm{C}$$, and the final volume in the lungs is 569 mL at $$37\ ^\circ\mathrm{C}. $$What was the initial volume of air inhaled, assuming constant pressure and amount of gas?

Accepted Answer

$$V_1 = 569$$\ \mathrm{mL} 	imes \frac{265\ \mathrm{K}}{310\ \mathrm{K}} = 486\ \mathrm{mL}$$

Question 11

A tank of nitrous oxide ($$N_2O) $$has a pressure of 48 psi. What is this pressure in atmospheres? (1 atm = 14.7 psi)

Accepted Answer

$$48\ \mathrm{psi} 	imes \frac{1\ \mathrm{atm}}{14.7\ \mathrm{psi}} = 3.3\ \mathrm{atm}$$

Question 12

Which of the following best describes the force of gas particles hitting the walls of a container?

Accepted Answer

Pressure

Question 13

A sample contains 8.00 g of $$O_2$$ gas with a volume of 5.00 L. If 4.00 g of $$O_2 is $$added (at constant T and P), what is the new volume?

Accepted Answer

$$V_2 = 5.00$$\ \mathrm{L} 	imes \frac{12.00\ \mathrm{g}}{8.00\ \mathrm{g}} = 7.50\ \mathrm{L}$$

Question 14

A mixture of cyclopropane ($$C_3H_6) $$and oxygen has a total pressure of 1.09 atm. If the partial pressure of cyclopropane is 73 mmHg, what is the partial pressure of oxygen in mmHg?

Accepted Answer

$$P_{O_2$} = 1.09\ \mathrm{atm} 	imes 760\ \mathrm{mmHg/atm} - 73\ \mathrm{mmHg} = 755\ \mathrm{mmHg}$$

Question 15

Which law would you use to solve a problem where pressure, volume, and temperature all change, but the amount of gas remains constant?

Accepted Answer

Combined Gas Law

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