Deck 12: Gas Laws

Question 1

Indicate the missing words in the following statement: "Gas laws describe in mathematical terms the relationships between the variables pressure, ________ and ________ for a fixed quantity of gas."

A) temperature; chemical identity
B) temperature; volume
C) volume; chemical identity
D) chemical identity; cost

Answer 1

temperature; volume

Question 2

Which of the following is/are characteristics of gases?

A) high compressibility
B) relatively long distances between molecules
C) formation of homogeneous mixtures regardless of the natures of non-reacting gas components
D) all of the above

Answer 2

all of the above

Question 3

Which of the following is not a unit used in measuring pressure?

A) atmosphere
B) inches Hg
C) kilometer Hg
D) millimeters Hg

Answer 3

kilometer Hg

Question 4

In terms of size, the mm Hg pressure unit is ________ the torr unit.

A) 100 times larger than
B) numerically equal to
C) 760 times larger than
D) 1000 times larger than

Question 5

What is standard atmospheric pressure in inches mercury (in Hg)? (2.54 cm = 1 in)

A) 1930 in Hg
B) 101 in Hg
C) 76.0 in Hg
D) 29.9 in Hg

Question 6

The barometric pressure in the eye of a hurricane sometimes dips as low as 27.2 inches mercury. How many millimeters of mercury is this?

A) 1.1 mm Hg
B) 6.9 mm Hg
C) 691 mm Hg
D) 107 mm Hg

Question 7

8.00 liters of oxygen gas is under a pressure of 280 torr. If the volume of this gas is increased to 14.00 liters at constant temperature, what will the new pressure be?

A) 66 torr
B) 490 torr
C) 387 torr
D) 160 torr

Question 8

Indicate what the missing words are in the following statement of Boyle's law: At constant temperature, the volume of a gas sample is ________ proportional to its ________.

A) directly, gas constant
B) directly, pressure
C) inversely, mass
D) inversely, pressure

Question 9

A 2.50 L sample of helium gas has a pressure of 0.925 atm. Calculate the pressure of the gas if the volume is reduced to 0.350 L at constant temperature.

A) 0.130 atm
B) 0.946 atm
C) 6.61 atm
D) 0.661 atm

Question 10

A mathematical statement of Charles' law is ________.

A) V₁T₁ = V₂T₂
B) V₁ + T₁ = V₂ + T₂
C) =
D) =

Question 11

Which of the following statements best gives the kinetic molecular theory explanation of the Boyle's law observation of increased pressure due to decreased volume?

A) Particles have more kinetic energy.
B) Particles increase in size.
C) Particles strike container walls with more force.
D) Particles strike container walls more frequently.

Question 12

Charles' law involves which of the following?

A) a varying temperature
B) a constant volume
C) a varying mass of gas
D) an indirect proportion

Question 13

10.0 liters of oxygen gas is at a temperature of 23 °C. If the temperature of the gas is raised to 40 °C at constant pressure the new volume will be ________.

A) 1.8 liters
B) 4.2 liters
C) 14.1 liters
D) 10.6 liters

Question 14

What is the final Celsius temperature if 6.48 L of H₂ gas at 22.0 °C is cooled until the volume reaches 3.77 L?

A) 24.8 °C
B) 113 °C
C) -205 °C
D) -101 °C

Question 15

If the volume of a sample of chlorine gas is reduced by 1/3 at constant pressure, what happens to its absolute temperature?

A) It remains constant.
B) It decreases by 1/3.
C) It triples.
D) It increases nine-fold.

Question 16

The Gay-Lussac's law observation of increased pressure due to increased temperature would be explained using kinetic theory in the following way: The pressure must increase because ________.

A) the molecules will strike the container walls less often
B) the molecules will strike the container walls more often
C) the molecules can move slower
D) the molecules can increase in size

Question 17

A mathematical statement of Gay-Lussac's law is ________.

A) P₁ + T₂ = P₂ + T₂
B) P₁T₁ = P₂T₂
C) =
D) =

Question 18

According to Gay-Lussac's law, if the pressure of a gas sample is doubled the gas sample ________.

A) volume decreases by a factor of 2
B) volume is doubled
C) Kelvin temperature decreases by a factor of 2
D) Kelvin temperature is doubled

Question 19

How would the pressure of a sealed container of gas be affected if its Kelvin temperature is halved while the moles and the volume of the gas remain constant?

A) The pressure would be reduced to one half of the original pressure.
B) The pressure would quadruple.
C) The pressure would not be affected.
D) The pressure would be reduced by a factor of 4.

Question 20

A cylinder of oxygen gas has a pressure of 6.00 atm at 25.0 °C. What is the pressure of the gas at 0.0 °C?

A) 5.50 atm
B) 6.55 atm
C) 2.40 atm
D) 15.0 atm

Question 21

According to the combined gas law, for a fixed amount of gas ________.

A) volume and pressure are directly proportional
B) volume and Kelvin temperature are inversely proportional
C) Kelvin and pressure are directly proportional
D) pressure and Kelvin temperature have no relationship to each other

Question 22

The combined gas law cannot be written as ________.

A)
B)
C)
D)

Question 23

If both the pressure and the Kelvin temperature of a gas are halved, the volume will ________.

A) double
B) quadruple
C) be halved
D) remain the same

Question 24

How will the pressure of a fixed sample of gas change if its volume is halved and its temperature is quadrupled (moles of gas remain constant)?

A) The pressure will increase by a factor of 4.
B) The pressure will increase by a factor of 8
C) The pressure will quadruple.
D) The pressure will decrease by a factor of 8.

Question 25

Syringe A has a specified volume of a gas at room temperature and atmospheric pressure. Which response below would not change the volume of gas in syringe A to the volume of gas shown in syringe B?

A) Decrease the pressure of the gas in syringe A at constant temperature.
B) Increase the temperature of the gas in syringe A at constant pressure.
C) Increase the pressure of the gas in syringe A at constant temperature.
D) Decrease the pressure, and increase the temperature on the gas in syringe A.

Question 26

A sample of nitrogen gas occupies a volume of 8.65 L at a temperature of 295 K and a pressure of 0.985 atm. What is the pressure of the gas if the volume of the gas is increased to 12.1 L and the temperature is reduced to 284 K?

A) 1.08 atm
B) 0.875 atm
C) 0.678 atm
D) 1.39 atm

Question 27

The conditions known as STP are ________.

A) 760 atm and 273 K
B) 760 mm Hg and 273 °C
C) 1 atm and 273 K
D) 1 mm Hg and 273 K

Question 28

A sample of N₂ gas occupies a volume 180 mL at STP. What volume, in L, will it occupy at 640 mm Hg and 295 K?

A) 0.231 L
B) 1.45 L
C) 1.07 L
D) 0.690 L

Question 29

Gay-Lussac's law of combining volumes states that the volumes of gases involved in a chemical reaction are in the same ratio as the coefficients for these gases in the balanced equation for the reaction provided that ________.

A) all volumes are measured in liters
B) all volumes are measured at the same temperature and pressure
C) all the gases have molecules that contain the same number of atoms
D) all the gases form diatomic molecules

Question 30

What volume of H₂ gas at 780 mm Hg and 23 °C is required to produce 10.6 L of NH₃ gas at the same temperature and pressure using the following chemical reaction?
N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g)

A) 15.9 L
B) 13.0 L
C) 20.0 L
D) 15.0 L

Question 31

Propane burners are used by campers for cooking purposes while in the wild. What volume of H₂O gas is produced by the complete combustion of 1.8 L of propane (C₃H₈) gas? All gas volumes are measured at the same temperature and pressure.
C₃H₈(g) + 5 O₂(g) $\rightarrow$ 3 CO₂(g) + 4 H₂O(g)

A) 1.8 L
B) 14 L
C) 7.2 L
D) 0.52 L

Question 32

At STP the volume of HCl that will result from the reaction of 0.680 L of H₂ and 0.750 L of Cl₂ is ________.
H₂(g) + Cl₂(g) $\rightarrow$ 2 HCl(g)

A) 0.680 L
B) 0.750 L
C) 1.36 L
D) 0.340 L

Question 33

Commercial ammonia is produced by reacting hydrogen gas with nitrogen gas according to the following equation.
N₂(g) + 3 H₂(g) $\rightarrow$ 2 NH₃(g)
If 6.00 × 10⁴ L of N₂ are reacted with 1.2 × 10⁵ L of H₂, the limiting reactant is ________ and the volume of ammonia produced is ________ L.

A) N₂, 3.33 x 10³
B) H₂, 6.00 x 10³
C) N₂, 8.00 x 10⁴
D) H₂, 8.00 x 10⁴

Question 34

Which of the following two variables are present in mathematical statements of Avogadro's law?

A) n and V
B) n and T
C) n and P
D) n, P, and V

Question 35

The molar volume of a gas is the volume occupied at STP by ________.

A) 22,400 mL of gas
B) 760 L of gas
C) 22.41 g of gas
D) 6.02 x 10²³ g of gas

Question 36

At standard conditions, one mole of any gas will occupy a volume of ________.

A) 1.00 liter
B) 22.41 mL
C) 22.41 L
D) 22,400 L

Question 37

What is the volume at STP, in liters, occupied by 26.4 g of F₂ gas?

A) 4.28 L
B) 15.6 L
C) 12.4 L
D) 11.8 L

Question 38

Three 1.0 L flasks filled with H₂, O₂ and He, respectively, are at STP. Which of the following statements concerning these gases is true?

A) Each flask contains the same number of atoms.
B) There are twice as many H₂ and O₂ molecules as there are He atoms.
C) There are twice as many He atoms as there are H₂ or O₂ molecules.
D) The number of H₂ or O₂ molecules is the same as the number of He atoms.

Question 39

What volume is occupied by 6.21 x 10²⁴ molecules of CO at STP?

A) 106 L
B) 230 L
C) 44.3 L
D) 231 L

Question 40

A 15.0 L cylinder was filled with of O₂ gas at STP. Calculate the number of O₂ molecules in the cylinder.

A) 4.03 x 10²³ molecules
B) 2.77 x 10²² molecules
C) 443 molecules
D) 6.59 x 10²⁴ molecules

Question 41

Calculate the density of butane (C₄H₁₀) in grams per liter at STP conditions.

A) 0.822 g/L
B) 2.60 g/L
C) 3.79 g/L
D) 5.48 g/L

Question 42

Calculate the density of ammonia (NH₃) gas in a 4.32 L container at 837 torr and 45 °C.

A) 3.86 g/L
B) 0.719 g/L
C) 0.432 g/L
D) 0.194 g/L

Question 43

The density of a gaseous chlorofluorocarbon (CFC) at 23.8 °C and 432 mmHg is 3.23 g/L. What is its molar mass?

A) 0.182 g/mol
B) 139 g/mol
C) 11.1 g/mol
D) 0.0146 g/mol

Question 44

6.80 L of CH₄ gas at 0.980 atm and 23 °C ________.

A) contains 0.897 mol CH₄
B) has a mass of 3.13 g
C) contains 6.02 x 10²² molecules CH₄
D) contains 6.61 x 10²³ H atoms

Question 45

The ideal gas equation cannot be written as ________.

A) PV = nRT
B) P =
C) R =
D) R =

Question 46

The value of the ideal gas constant, for the units (torr mL)/mole K is ________.

A) 0.0821
B) 1/0.0821
C) 62.4
D) 62,400

Question 47

The temperature, in °C, occupied by 0.643 moles of O₂ gas at 0.893 atm pressure and a volume of 14.7 L is ________.

A) 16 °C
B) -24 °C
C) 48 °C
D) 318 °C

Question 48

At what temperature in °C does 0.444 mole of carbon monoxide, CO, occupy 11.8 L at 889 mmHg?

A) 51 °C
B) 14 °C
C) 32 °C
D) 106 °C

Question 49

Calculate the volume of 12.0 g of helium at 54.5 °C and 1025 mm Hg.

A) 59.8 L
B) 13.9 L
C) 24.6 L
D) 77.4 L

Question 50

Which of the following is a correct expression for the molecular mass of a gas?

A)
B)
C)
D)

Question 51

Of the following gases, the one with the greatest density at STP is ________.

A) NO
B) N₂
C) O₂
D) CO₂

Question 52

The density of a gas is 1.34 g/L at STP. What is the mass of one mole of this gas?

A) 30.0 g
B) 28.0 g
C) 44.0 g
D) 43.9 g

Question 53

What is the density of F₂, if the temperature is 24.0 °C and the pressure is 0.986 atm?

A) 1.24 g/L
B) 1.54 g/L
C) 2.04 g/L
D) 1.96 g/L

Question 54

Which noble gas has a density of 5.86 g/L at STP?

A) Ne
B) Ar
C) Kr
D) Xe

Question 55

A 0.50 L cylinder contains 0.820 grams of an unknown gas. The pressure inside the cylinder is 2.50 atmospheres at 25.0 °C. What is the identity of the unknown gas?

A) 28.0 g/mol, N₂
B) 2.02 g/mol, H₂
C) 16.0 g/mol, CH₄
D) 38.0 g/mol, F₂

Question 56

0.2050 g of a liquid was added to an Erlenmeyer flask. The temperature inside the flask was 35.°C. The volume of the flask was 125 mL. The molecular weight of the liquid was 44.0 g/mole. Calculate the pressure inside the flask in mm Hg.

A) 460 mm Hg
B) 58.1 mm Hg
C) 717 mm Hg
D) 1.40 x 10³ mm Hg

Question 57

At 150 °C and 1.00 atm, 500 mL of a vapor has a mass of 0.8365 g. What is the molecular weight of the compound?

A) 110 g/mol
B) 116 g/mol
C) 130 g/mol
D) 58.1 g/mol

Question 58

In the reaction Fe₂O₃ + 3H₂ $\rightarrow$ 2Fe + 3H₂O, how many grams of Fe₂O₃ must react to produce 10.8 liters of H₂O at STP?

A) 25.7 g
B) 12.6 g
C) 65.3 g
D) 648 g

Question 59

How many grams of sodium azide, NaN₃ (molar mass = 65.02) are needed to react by the equation below in order to inflate a 66.0 L air bag with N₂(g) at 294 K and 0.989 atm pressure?
2 NaN₃(s) $\rightarrow$ 2 Na(s) + 3 N₂(g)

A) 44.2 g
B) 60.1 g
C) 95.1 g
D) 117 g

Question 60

Electrolysis of 12.6 g of water would produce what volume of O₂ gas at 640 torr and
22)0 °C?
2 H₂O (l) + electricity $\rightarrow$ 2 H₂(g) + O₂(g)

A) 10.1 L
B) 44.8 L
C) 22.4 L
D) 68.4 L

Question 61

What volume of H₂, in milliliters, at 21 °C and 0.998 atm can be produced from the reaction of 2.40 grams of Zn in excess HCl?
Zn(s) + 2 HCl(aq) $\rightarrow$ ZnCl₂(aq) + H₂(g)

A) 890 mL
B) 675 mL
C) 3300 mL
D) 1200 mL

Question 62

The pressure exerted by a gas collected by water displacement is obtained by subtracting the vapor pressure of H₂O from the total pressure of the gas collected. This is an example of the application of ________.

A) Avogadro's law
B) Dalton's law
C) Boyle's law
D) Charles' law

Question 63

What is the volume occupied by a mixture of 25.7 g of NO₂ and 13.9 g of SO₂ at STP?

A) 11.2 L
B) 22.4 L
C) 17.4 L
D) 26.9 L

Question 64

A mixture of 8.95 g of Cl₂ and 18.0 g of NO₂ and an undetermined amount of SO₂ occupies a volume of 22.4 liters at 760 mm Hg and 0 °C. How many moles of SO₂ are present?

A) 1.06 moles
B) 2.77 moles
C) 0.381 moles
D) 0.483 moles

Question 65

What is the partial pressure of N₂ in a mixture of 0.36 mole N₂, 0.15 mole Ne, and 0.75 mole of O₂ that has a total pressure of 3.18 atm?

A) 0.29 atm
B) 0.36 atm
C) 0.65 atm
D) 0.91 atm

Question 66

What is the total pressure in a 4.00 L flask at 298 K, that contains 2.6 moles of He, 0.8 mole of Ne, 1.6 moles of O₂?

A) 2.6 atm
B) 4.9 atm
C) 31 atm
D) 25 atm

Question 67

What is the volume percent of Ar in a 6.50 L flask that contains 0.200 mole of Ne, 0.300
Mole He, 0.600 mole of Ar at STP?

A) 36.4%
B) 54.5%
C) 44.3%
D) 21.9%

Question 68

An excimer laser contains 0.40 mole Ar and 0.60 mole F₂. The total pressure inside the laser cavity is 1.10 atm. What is the partial pressure of Ar inside the laser?

A) 0.40 atm
B) 0.44 atm
C) 0.60 atm
D) 1.00 atm

Question 69

A sample of SO₃ gas is decomposed to SO₂ and O₂.
2 SO₃(g) $\rightarrow$ 2 SO₂(g) + O₂(g)
If the total pressure of SO₂ and O₂ is 1340 torr, calculate the partial pressure of O₂ in torr.

A) 1340 torr
B) 893 torr
C) 447 torr
D) 1160 torr

Question 70

A gas has a volume of 225 mL at a pressure of 162.5 torr. What is the pressure (in atm) if the volume is decreased to 45 mL?

Question 71

A quantity of gas has a volume of 3560 mL at a temperature of 55 °C and a pressure of 850 torr. What is the temperature (in °C) if the volume remains unchanged but the pressure is decreased to 0.652 atm?

Question 72

Chlorine gas is widely used to purify municipal water supplies and to treat swimming pool waters. Suppose that the volume of a particular sample of Cl₂ is 6.18 L at 0.884 atm and 46 °C, at what temperature (in °C) will the volume be 2.00 L if the pressure is 157 kPa?

Question 73

A sample of helium gas has a volume of 1.25 L at -125 °C and 5.00 atm. This gas is compressed at 50.0 atm to a volume of 325 mL. What is the final temperature of the helium gas in °C?

Question 74

What is the pressure, exerted by 1.00 x 10²⁰ molecules of nitrogen in a 305 mL flask at
175 °C?

Question 75

An unknown gas with a mass of 4.52 g was found to occupy a volume of 875 mL at 1.69 atm and 65 °C. What is the molecular weight of this gas?

Question 76

Monochloroethylene is used to make polyvinylchloride (PVC). It has a density of 2.56 g/L at 22.8 °C and 756 mmHg. What is the molar mass of monochloroethylene?

Question 77

What mass of NH₃ gas has a volume of 16,400 mL, a pressure of 0.955 atm and a temperature of -23 °C?

Question 78

A mixture of 8.50 g of hydrogen and 15.0 g of helium in a 7.3 L flask is maintained at 15.0 °C. What is the total pressure in the container?