Question 1

A high-performance road bicycle tire is inflated to a total pressure of 132 psi. What is this pressure in mmHg? (1 atm = 14.7 psi, 1 atm = 760 mmHg)

Accepted Answer

$$6.82 	imes 10^3$ mmHg

Question 2

A weather report announces the barometric pressure is 30.44 in Hg. What is this pressure in psi? (1 atm = 29.92 in Hg, 1 atm = 14.7 psi)

Accepted Answer

$$14.95$$ psi

Question 3

A woman has an initial lung volume of 2.75 L at 1.02 atm. If she increases her lung volume to 3.25 L without inhaling or exhaling, what is the new pressure in her lungs? (Assume Boyle's Law applies.)

Accepted Answer

$$0.863$$ atm

Question 4

A gas sample has a volume of 2.80 L at an unknown temperature. When the sample is submerged in ice water at $$0.00^\circC$$, its volume decreases to 2.57 L. What was its original temperature in $$^\circC$$?

Accepted Answer

$$24^\circC$$

Question 5

A deep inhalation fills an athlete's lungs to 6.15 L with 0.254 mol of air. After exhalation, the lung volume is 2.55 L. How many moles of air remain in the lungs after exhalation (assume constant temperature and pressure)?

Accepted Answer

$$0.105$$ mol

Question 6

Calculate the volume occupied by 0.845 mol of nitrogen gas at a pressure of 1.37 atm and a temperature of 315 K. (Use $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$15.9 L$$

Question 7

A 3.24-L basketball is filled to a total pressure of 24.3 psi at 25$$^\circC. $$How many moles of gas are in the basketball? (1 atm = 14.7 psi, $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$0.219$$ mol

Question 8

What is the density of nitrogen gas at 125$$^\circC $$and a pressure of 755 mmHg? (Molar mass of N$$_2 = 28.02 g/$$mol, $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1}$$, 1 atm = 760 mmHg)

Accepted Answer

$$0.852 g/L$$

Question 9

A sample of gas has a mass of 0.311 g, a volume of 0.225 L, a temperature of 55$$^\circC$$, and a pressure of 886 mmHg. What is its molar mass? (1 atm = 760 mmHg, $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$31.9 g/$$mol

Question 10

A 100-L mixture of helium, neon, and argon has a total pressure of 662 mmHg at 298 K. If the partial pressures of helium and neon are 341 mmHg and 112 mmHg, respectively, what mass of argon is present? (Molar mass of Ar = 39.95 g/mol, $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1}$$, 1 atm = 760 mmHg)

Accepted Answer

$$0.449 g$$

Question 11

A 125-L scuba tank contains a mixture of 24.2 g He and 4.32 g O$$_2 at 298 K. $$What is the mole fraction of oxygen in the mixture? (Molar mass He = 4.00 g/mol, O$$_2 = 32.00 g/$$mol)

Accepted Answer

$$0.0218$$

Question 12

Oxygen gas is collected over water at 20$$^\circC $$and a total pressure of 755.2 mmHg. If the vapor pressure of water at 20$$^\circC is 17.55 $$mmHg, what is the partial pressure of oxygen?

Accepted Answer

$$737.65$$ mmHg

Question 13

Methanol (CH$$_3OH) is $$synthesized by the reaction: CO(g) + 2 H$$_2(g$$) $$\rightarrow CH$_3OH(g). $$What volume of H$$_2$$ gas at 355 K and 738 mmHg is needed to synthesize 35.7 g of methanol? (Molar mass CH$$_3OH = 32.04 g/$$mol, $$R = 0.08206 L$$·atm·mol$$^{-1}$$·K$$^{-1}$$, 1 atm = 760 mmHg)

Accepted Answer

$$66.9 L$$

Question 14

How many grams of water form when 1.24 L of H$$_2$$ gas at STP completely reacts with O$$_2$$? (2 H$$_2(g) + O$_2(g$$) $$\rightarrow 2 H$_2O(g$$), 1 mol gas = 22.4 L at STP, Molar mass H$$_2O = 18.02 g/$$mol)

Accepted Answer

$$0.998 g$$

Question 15

Calculate the root mean square velocity ($$u_{rms}) of O$_2$$ molecules at 25$$^\circC. ($$Molar mass O$$_2 = 32.00 g/$$mol, $$R = 8.314 J$$·mol$$^{-1}$$·K$$^{-1}$$, $$u_{rms} = \sqrt{\frac{3RT}{M}}$$, M in kg/mol)

Accepted Answer

$$482 m/s$$

Question 16

An unknown gas effuses at a rate that is 0.462 times that of nitrogen gas (N$$_2) at $$the same temperature. What is the molar mass of the unknown gas? (Molar mass N$$_2 = 28.02 g/$$mol, Graham's law: $$\frac{	ext{rate}_1}{	ext{rate}_2} = \sqrt{\frac{M_2$}{M_1$}})$$

Accepted Answer

$$131 g/$$mol

Question 17

A diver breathes a heliox mixture with an oxygen mole fraction of 0.050. What must the total pressure be for the partial pressure of oxygen to be 0.20 atm?

Accepted Answer

$$4.0$$ atm

Question 18

A sample of hydrogen gas is mixed with water vapor. The mixture has a total pressure of 755 torr, and the water vapor has a partial pressure of 24 torr. What is the partial pressure of hydrogen gas?

Accepted Answer

$$731$$ torr

Chapter 6: Gases – General Chemistry Study Notes

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