Deck 10: Gases: Their Properties and Behavior

Question 1

If the pressure in a gas container that is connected to an open-end U-tube manometer is 106 kPa and the pressure of the atmosphere at the open end of the tube is 700 mm Hg,the level of mercury in the tube will be

A)95 mm higher in the arm open to the atmosphere.
B)95 mm higher in the arm connected to the gas cylinder.
C)795 mm higher in the arm open to the atmosphere.
D)795 mm higher in the arm connected to the gas cylinder.

Answer 1

95 mm higher in the arm open to the atmosphere.

Question 2

The SI unit for pressure is the

A)atmosphere.
B)MM Hg.
C)newton.
D)pascal.

Answer 2

pascal.

Question 3

Which of the following instruments directly measures the pressure of a gas?

A)spectrometer
B)manometer
C)polarimeter
D)gas chromatograph

Answer 3

manometer

Question 4

The volume of 350.mL of gas at 25°C is decreased to 250.mL at constant pressure.What is the final temperature of the gas?

A)-60.1°C
B)213°C
C)17.8°C
D)144°C

Question 5

What is the pressure in a gas container that is connected to an open-end U-tube manometer if the pressure of the atmosphere is 752 torr and the level of mercury in the arm connected to the container is 9.60 cm higher than the level of mercury open to the atmosphere?

A)656 mm Hg
B)742 mm Hg
C)762 mm Hg
D)848 mm Hg

Question 6

When pressure-volume measurements are made on 1.0 mol of gas at constant temperature,a plot V versus P results in a

A)hyperbola.
B)parabola.
C)sine curve.
D)straight line.

Question 7

A basketball is inflated to a pressure of 2.10 atm in a 20.0°C garage.What is the pressure of the basketball outside where the temperature is -5.00°C?

A)1.92 atm
B)2.29 atm
C)2.10 atm
D)2.50 atm

Question 8

Which of the following equations represents "Boyle's law"?

A)
= k
B)
= k
C)PV = k
D)V = nk

Question 9

Pressure is defined as

A)force divided by unit area.
B)force times unit area.
C)mass divided by acceleration.
D)mass times acceleration.

Question 10

When temperature-volume measurements are made on 1.0 mol of gas at 1.0 atm,a plot V versus T results in a

A)hyperbola.
B)parabola.
C)sine curve.
D)straight line.

Question 11

A container filled with gas is connected to an open-end U-tube manometer that is filled with mineral oil.The pressure in the gas container is 770 mm Hg and atmospheric pressure is 754 mm Hg.What will be the difference in the levels of mineral oil in the two arms of the manometer if the densities of Hg and mineral oil are 13.6 g/mL and 0.822 g/mL respectively?

A)1.15 mm
B)15.6 mm
C)16.0 mm
D)264 mm

Question 12

If mercury (density = 13.6 g/cm³)at a height of 745 mm Hg in a mercury barometer is replaced with water (density = 1.00 g/cm³),under the same conditions the height of water will be

A)0.180 ft.
B)2.44 ft.
C)33.2 ft.
D)399 ft.

Question 13

Suppose you needed to closely monitor small changes in pressure inside a container using an open end manometer.For the best accuracy,the substance in the manometer should

A)be a solid.
B)be mercury.
C)have a high density.
D)have a low density.

Question 14

In an open end manometer,one end of a U-tube filled with mercury is attached to a gas-filled container and the other end is open to the atmosphere.If the gas pressure in the container is less than atmospheric pressure

A)Hg will be forced out of the open end of the U-tube.
B)the difference between the Hg levels in the two arms will be greater than 76 cm.
C)the Hg level will be higher in the arm connected to the container.
D)the Hg level will be higher in the arm open to the atmosphere.

Question 15

An approximation of absolute zero was made from an extrapolation of

A)P vs.1/V.
B)V vs.T.
C)n vs.V.
D)V vs.1/T.

Question 16

Which law does the equation, = k represent?

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

Question 17

Automobile tires are typically inflated to about 30 pounds of pressure per square inch.What is the typical air pressure of a tire in kPa?

A)2.0 × 10^-3 kPa
B)2.0 kPa
C)2.1 × 10² kPa
D)2.1 × 10⁵ kPa

Question 18

"Equal volumes of different gases at the same temperature and pressure contain the same molar amounts" is another way of stating

A)Avogadro's law.
B)Boyle's law.
C)Charles' law.
D)Graham's law.

Question 19

A gas bottle contains 0.800 mol of gas at 730 mm Hg pressure.If the final pressure is 1.15 atm,how many moles of gas were added to the bottle?

A)0.0012 mol
B)0.158 mol
C)0.958 mol
D)0.0668 mol

Question 20

Which is the smallest quantity of pressure?

A)1 atm
B)1 centimeter of Hg
C)1 mm Hg
D)1 pascal

Question 21

A 1.00 L flask contains nitrogen gas at 25°C and 1.00 atm pressure.What is the final pressure in the flask if an additional 0.50 g of N₂ gas is added to the flask and the flask cooled to -55°C?

A)1.01 atm
B)1.05 atm
C)0.319 atm
D)3.13 atm

Question 22

For an ideal gas,which pairs of variables are inversely proportional to each other (if all other factors remain constant)? I.P,T II.P,V III.V,T IV.n,T

A)I and II only
B)III and IV only
C)II only
D)I and III only

Question 23

What is the density of carbon monoxide gas at STP?

A)0.510 g/L
B)0.800 g/L
C)1.96 g/L
D)1.25 g/L

Question 24

You have two samples of the same gas in the same size container,with the same pressure.The gas in the first container has a Kelvin temperature four times that of the gas in the other container.The ratio of the number of moles of gas in the first container compared to that in the second is

A)1:1.
B)1:2.
C)1:4.
D)4:1.

Question 25

A 0.429-g sample of gas occupies 125 mL at 60.cm of Hg and 25°C.What is the molar mass of the gas?

A)8.9 g/mol
B)66 g/mol
C)88 g/mol
D)106 g/mol

Question 26

A 1.75 L container filled with CO₂ gas at 25°C and 225 kPa pressure springs a leak.When the container is re-sealed,the pressure is 200 kPA and the temperature is 10°C.How many moles of gas were lost?

A)0.0101 mol
B)0.149 mol
C)6.71 mol
D)99.0 mol

Question 27

A gas occupies 22.4 L at STP and 9.85 L at 100.°C and 2.00 atm pressure.How many moles of gas did the system gain or lose?

A)1.36 moles gained
B)1.64 moles gained
C)0.644 moles lost
D)0.356 moles lost

Question 28

A steel bottle contains argon gas at STP.What is the final pressure if the temperature is changed to 85°C?

A)0.666 atm
B)0.762 atm
C)0.850 atm
D)1.31 atm

Question 29

What is the value of the gas constant,R,in units of ?

A)1.080 × 10^-4
B)0.1080
C)62.36
D)6.236 × 10⁴

Question 30

Chloroform is a volatile liquid once commonly used in the laboratory but now being phased out due to its ozone depletion potential.If the pressure of gaseous chloroform in a flask is 195 mm Hg at 25°C and its density is 1.25 g/L,what is the molar mass of chloroform?

A)10.0 g/mol
B)76.3 g/mol
C)119 g/mol
D)None of these

Question 31

What is the Celsius temperature of 100.0 g of chlorine gas in a 4.00-L container at 800 mm Hg?

A)309°C
B)-236°C
C)236°C
D)-309°C

Question 32

Three identical flasks contain three different gases at standard temperature and pressure.Flask A contains Ar,flask B contains Ne,flask C contains H₂.Which flask contains the largest number of molecules?

A)flask A
B)flask B
C)flask C
D)All flasks contain the same number of molecules.

Question 33

How many grams of H₂ gas are there in a 5.00-L cylinder at 4.00 × 10³ mm Hg and 23°C?

A)1.08 g
B)2.16 g
C)0.542 g
D)823 g

Question 34

A balloon filled with helium gas at 20°C occupies 2.91 L at 1.00 atm.The balloon is immersed in liquid nitrogen at -180°C,raising the pressure to 5.20 atm.What is the volume of the balloon in the liquid nitrogen?

A)0.178 L
B)5.62 L
C)5.04 L
D)0.199 L

Question 35

The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s)+ 2 Al(s)+ 6 H₂O(l)→ 2 NaAl(OH)₄(s)+ 3 H₂(g)
What is the volume of H₂ gas formed at STP when 8.64 g of Al reacts with excess NaOH?

A)4.78 L
B)7.18 L
C)10.8 L
D)11.7 L

Question 36

How many molecules of N₂ are in a 250.0 mL container at 780 mm Hg and 135°C?

A)4.38 × 10²¹ molecules
B)4.62 × 10²¹ molecules
C)1.32 × 10²² molecules
D)1.39 × 10²² molecules

Question 37

Cyanogen is a gas which contains 46.2% C and 53.8% N by mass.At a temperature of 25°C and a pressure of 750 mm Hg,1.50 g of cyanogen occupies 0.714 L.What is the molecular formula of cyanogen?

A)CN
B)C₂N₂
C)C₃N₄
D)C₄N₅

Question 38

A 75.0 L steel tank at 20.0°C contains acetylene gas,C₂H₂,at a pressure of 1.20 atm.Assuming ideal behavior,how many grams of acetylene are in the tank?

A)3.74 g
B)54.8 g
C)97.3 g
D)1425 g

Question 39

What is the volume of 10.0 g of oxygen gas at 157°C and 2.50 kPa pressure?

A)51.5 L
B)163 L
C)1.61 L
D)447 L

Question 40

Which of the following would have a density of 1.89 g/L at 7.0°C and 0.987 atm?

A)Ar
B)CO₂
C)CO
D)O₂

Question 41

How many liters of SO₃(g)are produced at 25°C and 1.00 atm from the combustion of 1.00 kg of coal which is 1.00% S by weight? Assume all the sulfur in the coal ends up as SO₃.

A)0.640 L
B)5.08 L
C)7.63 L
D)11.4 L

Question 42

Some assumptions from the kinetic molecular theory are listed below.Which one is most frequently cited to explain diffusion of a gas?

A)The average kinetic energy of gas particles is proportional to the Kelvin temperature.
B)Collisions of gas particles are elastic and total kinetic energy of the gas is constant.
C)A gas consist of tiny particles moving in random straight line motion.
D)The volume of the particles is negligible compared to the volume of the gas.

Question 43

How many liters of oxygen are needed to exactly react with 55.6 g of methane at STP? CH₄(g)+ 2 O₂(g)→ CO₂(g)+ 2 H₂O(l)

A)19.5 L
B)39.0 L
C)156 L
D)77.8 L

Question 44

At STP how many liters of NH₃ can be produced from the reaction of 6.00 mol of N₂ with 6.00 mol of H₂? N₂(g)+ 3 H₂(g)→ 2 NH₃(g)

A)44.8 L
B)89.6 L
C)134 L
D)269 L

Question 45

If the Earth's ozone (O₃)layer has a total volume of 1.00 × 10²⁰ km³,a partial pressure of 1.6 × 10^-9 atm,and an average temperature of 230 K,how many ozone molecules are in the Earth's ozone layer?

A)2.3 × 10³⁵ molecules
B)5.1 × 10³⁵ molecules
C)2.3 × 10⁴⁵ molecules
D)5.1 × 10⁴⁵ molecules

Question 46

Some assumptions from the kinetic molecular theory are listed below.Which one is most frequently cited to explain Charles' law?

A)The average kinetic energy of gas particles is proportional to the Kelvin temperature.
B)Collisions of gas particles are elastic and total kinetic energy of the gas is constant.
C)A gas consists of tiny particles moving in random straight line motion.
D)The volume of the particles is negligible compared to the volume of the gas.

Question 47

Two moles of neon gas at 20.0°C are heated to 350°C while the volume is kept constant.The density of the gas

A)decreases.
B)increases.
C)remains the same.
D)Not enough information was given to answer the question.

Question 48

The ozone molecules in the stratosphere absorb much of the ultraviolet radiation from the sun,protecting life on Earth.At a certain altitude,the temperature of the stratosphere is 240 K and the partial pressure of ozone is 1.4 × 10^-7 atm.Calculate the number of ozone molecules present in 1.00 L of atmosphere at that altitude.

A)2.1 × 10¹⁵ molecules of O₃
B)4.3 × 10¹⁵ molecules of O₃
C)8.0 × 10³¹ molecules of O₃
D)1.8 × 10³² molecules of O₃

Question 49

In the laboratory,hydrogen gas is usually made by the following reaction: Zn(s)+ 2 HCl(aq)→ H₂(g)+ ZnCl₂(aq)
How many liters of H₂ gas,collected over water at an atmospheric pressure of 752 mm Hg and a temperature of 21.0°C,can be made from 3.132 g of Zn and excess HCl? The partial pressure of water vapor is 18.65 mm Hg at 21.0°C.

A)0.0856 L
B)1.15 L
C)1.17 L
D)1.20 L

Question 50

Some assumptions from the kinetic molecular theory are listed below.Which one is most frequently cited to explain compressibility of a gas?

A)The average kinetic energy of gas particles is proportional to the Kelvin temperature.
B)Collisions of gas particles are elastic and total kinetic energy of the gas is constant.
C)A gas consist of tiny particles moving in random straight line motion.
D)The volume of the particles is negligible compared to the volume of the gas.

Question 51

When 30.0 g of zinc metal reacts with excess HCl,how many liters of H₂ gas are produced at STP?

A)0.229 L
B)0.458 L
C)5.14 L
D)10.3 L

Question 52

According to the kinetic molecular theory,the pressure of a gas in a container will decrease if the

A)number of collisions with the container wall increases.
B)number of moles of the gas increases.
C)temperature of the gas decreases.
D)volume of the container decreases.

Question 53

How many grams of XeF₆ are required to react with 1.16 L of hydrogen gas at 2.46 atm and 45°C in the reaction shown below? XeF₆(s)+ 3 H₂(g)→ Xe(g)+ 6 HF(g)

A)7.30 g
B)8.92 g
C)26.8 g
D)80.4 g

Question 54

What is the total pressure in a 10.0 L flask which contains 0.200 mol of H₂(g)and 0.215 mol of N₂(g)at 20.0°C?

A)0.306 atm
B)0.681 atm
C)0.693 atm
D)0.998 atm

Question 55

A balloon contains 0.76 mol N₂,0.18 mol Ar,0.031 mol He,and 0.026 mol H₂ at 739 mm Hg.What is the partial pressure of Ar?

A)19 mm Hg
B)23 mm Hg
C)130 mm Hg
D)560 mm Hg

Question 56

What is the average speed (actually the root-mean-square speed)of a carbon monoxide molecule at 27°C?

A)450 m/s
B)412 m/s
C)514 m/s
D)517 m/s

Question 57

Hydrogen gas is collected over water in an inverted buret.If the atmospheric pressure is 745 mm Hg,the vapor pressure of water is 18 mm Hg,and a 15.0 cm-high column of water remains in the buret,the pressure of the hydrogen gas is

A)763 mm.
B)745 mm Hg.
C)727 mm Hg.
D)less than 727 mm Hg.

Question 58

A 2.000 kg sample of nitroglycerine,C₃H₅N₃O₉,explodes and releases gases with a temperature of 1985°C at 1.000 atm.What is the volume of gas produced? 4 C₃H₅N₃O₉(l)→ 12 CO₂(g)+ 10 H₂O(g)+ 6 N₂(g)+ O₂(g)

A)1632 L
B)7756 L
C)10410 L
D)11830 L

Question 59

A lungful of air (500 mL)contains 4.1% CO₂ by volume.How many grams of KO₂(s)is needed to remove the CO₂ from a lungful of air at STP according to the following reaction? 4 KO₂(s)+ 2 CO₂(g)→ 2 K₂CO₃(s)+ 3 O₂(g)

A)0.065 g
B)0.13 g
C)0.26 g
D)1.2 g

Question 60

A 0.500 g sample containing Ag₂O and inert material is heated,causing the silver oxide to decompose according to the following equation: 2 Ag₂O(s)→ 4 Ag(s)+ O₂(g)
If 6.90 mL of gas are collected over water at 27°C and 1.00 atm external pressure,what is the percentage of silver oxide in the sample? The partial pressure of water is 26.7 mm Hg at 27°C.

A)6.25%
B)12.5%
C)25.0%
D)26.0%

Question 61

Each of three identical 15.0-L gas cylinders contains 7.50 mol of gas at 295 K.Cylinder A contains Ar,cylinder B contains Cl₂,and cylinder C contains N₂.According to the kinetic molecular theory,which gas has the highest collision frequency?

A)Ar
B)Cl₂
C)N₂
D)All have identical collision frequencies

Question 62

Which statement about real gases is true?

A)The volume of the gas particles is zero.
B)The mass of the gas particles is zero.
C)Forces of attraction and repulsion exist between gas particles at close range.
D)The behavior of real gases can be exactly predicted using the ideal gas law.

Question 63

Which of the following is the principal cause of global warming?

A)acid rain
B)air pollution
C)greenhouse effect
D)ozone depletion

Question 64

Which of the noble gases should show the greatest deviation from the ideal gas law at high pressures?

A)He
B)Ar
C)Rn
D)All deviate equally.

Question 65

If CO₂ and NH₃ are allowed to effuse through a porous membrane under identical conditions,the rate of effusion for NH₃ will be ________ times that of CO₂.

A)0.39
B)0.62
C)1.6
D)2.6

Question 66

What is the temperature of N₂ gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s?

A)0.842 K
B)6.31 × 10² K
C)3.16 × 10² K
D)0.421 K

Question 67

An unknown gas effuses 2.3 times faster than N₂O₄ at the same temperature.What is the identity of the unknown gas?

A)CN₂
B)NH₃
C)N₂O
D)O₃

Question 68

Which of the following regions of the earth's atmosphere is closest to the surface of the earth?

A)mesosphere
B)stratosphere
C)thermosphere
D)troposphere

Question 69

One reaction that contributes to photochemical smog is shown below.Which of the species involved contains one or more unpaired electrons? NO₂(g)+ hυ →NO(g)+ O(g)

A)only NO₂(g)
B)only NO₂(g)and NO(g)
C)only O(g)
D)All of the these contain unpaired electrons.

Question 70

What is the pressure (in mm Hg)of the gas inside the above apparatus if the outside pressure,P_atm,is 750 mm Hg and the difference in mercury levels,Δh,is 50 mm Hg?

A)50 mm Hg
B)700 mm Hg
C)750 mm Hg
D)800 mm Hg

Question 71

Which of the following regions of the earth's atmosphere contains the ozone layer?

A)mesosphere
B)stratosphere
C)thermosphere
D)troposphere

Question 72

The lowest atmospheric temperatures are found at the

A)earths surface.
B)troposphere/stratosphere junction.
C)stratosphere/mesosphere junction.
D)mesosphere/thermosphere junction.

Question 73

Which of the following regions of the earth's atmosphere is farthest from the surface of the earth?

A)mesosphere
B)stratosphere
C)thermosphere
D)troposphere

Question 74

You are given two flasks of equal volume.One contains H₂ at 0°C and 1 atm while the other contains CO₂ at and 2 atm.Which of the following quantities will be the same for both flasks?

A)average molecular kinetic energy
B)average molecular speed
C)density
D)number of molecules present

Question 75

An unknown gas effuses 1.73 times faster than krypton.What is the molar mass of the gas?

A)28.0 g/mol
B)48.4 g/mol
C)110 g/mol
D)251 g/mol

Question 76

At what temperature will sulfur hexafluoride molecules have the same average speed as argon atoms at 20°C?

A)-22.0°C
B)73.2°C
C)381°C
D)799°C

Question 77

What is the pressure (in mm Hg)of the gas inside the above apparatus if the outside pressure,P_atm,is 740 mm Hg and the difference in mercury levels,Δh,is 30 mm Hg?

A)30 mm Hg
B)710 mm Hg
C)740 mm Hg
D)770 mm Hg

Question 78

An unknown gas contains 83% C and 17% H by mass.If effuses at 0.87 times the rate of CO₂ gas under the same conditions.What is the molecular formula of the unknown gas?

A)C₂H₅
B)C₃H₃
C)C₄H₁₀
D)C₇H₁₇

Question 79

Which of the following substances has increased markedly due to the use of fossil fuels and contributes to the greenhouse effect?

A)CO₂
B)SO₂
C)NO₂
D)O₃

Question 80

A greenhouse gas is a gas that can experience a change in dipole moment.Which of the following can be greenhouse gases?

A)O₂
B)H₂
C)N₂
D)CH₃F