Deck 5: Gases

Question 1

To what temperature must a balloon,initially at 25^∘C and 2.00 L,be heated in order to have a volume of 6.00 L?

A)993 K
B)403 K
C)75 K
D)655 K
E)894 K

Answer 1

894 K

Question 2

What mass of NO₂ is contained in a 13.0 L tank at 4.58 atm and 385 K?

A)18.8 g
B)53.1 g
C)24.4 g
D)86.7 g
E)69.2 g

Answer 2

86.7 g

Question 3

What pressure (in atm)will 0.44 moles of CO₂ exert in a 2.6 L container at 25°C?

A)0.35 atm
B)4.1 atm
C)4.7 atm
D)8.6 atm
E)3.6 atm

Answer 3

4.1 atm

Question 4

A syringe contains 0.65 moles of He gas that occupy 750.0 mL.What volume (in L)of gas will the syringe hold if 0.35 moles of Ne is added?

A)0.87 L
B)4.9 L
C)1.2 L
D)2.1 L
E)1.9 L

Question 5

If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions,what volume will 0.66 moles occupy under the same conditions?

A)12 L
B)8.6 L
C)17 L
D)5.0 L
E)15 L

Question 6

To what volume will a sample of gas expand if it is heated from 50.0°C and 2.33 L to 500.0°C?

A)5.58 L
B)9.74 L
C)10.3 L
D)17.9 L
E)4.38 L

Question 7

In Boyle's Law,

A)volume is inversely proportional to pressure.
B)volume is proportional to pressure.
C)pressure is inversely proportional to temperature.
D)volume is proportional to temperature.

Question 8

The volume of a gas is proportional to the temperature of a gas is known as

A)Avogadro's Law.
B)Ideal Gas Law.
C)Charles's Law.
D)Boyle's Law.

Question 9

How many molecules of CO₂ are contained in a 10.0 L tank at 7.53 atm and 485 K?

A)1.89 × 10²⁴ molecules
B)1.14 × 10²⁴ molecules
C)8.32 × 10²⁴ molecules
D)4.89 × 10²⁴ molecules
E)3.63 × 10²⁴ molecules

Question 10

A sample of 0.300 moles of nitrogen occupies 0.600 L.Under the same conditions,what amount of moles occupies 1.200 L?

A)0.600 moles
B)1.50 moles
C)0.33 moles
D)6.00 moles

Question 11

What pressure will 14.0 g of CO exert in a 3.5 L container at 75°C?

A)4.1 atm
B)5.0 atm
C)6.4 atm
D)1.1 atm
E)2.3 atm

Question 12

What pressure will 2.6 × 10²³ molecules of H₂ exert in a 3.9 L container at 45°C?

A)5.7 atm
B)1.7 atm
C)2.9 atm
D)3.4 atm
E)4.6 atm

Question 13

Calculate the temperature,in K,of 2.20 moles of gas occupying 3.50 L at 3.30 atm.

A)64.0 K
B)5.25 K
C)337 K
D)28.0 K

Question 14

What volume will a balloon occupy at 1.0 atm,if the balloon has a volume of 7.6 L at 3.8 atm?

A)2.0 L
B)5.0 L
C)29 L
D)35 L
E)17 L

Question 15

What pressure (in atm)will a sample of O₂ gas occupy at 100.0 mL,if O₂ has a volume of 25.00 mL at 2.0 atm?

A)4.0 atm
B)2.0 atm
C)125.atm
D)0.50 atm
E)8.00 atm

Question 16

A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mm Hg.What volume of gas will the balloon contain at 1.35 atm and 253 K?

A)22.2 L
B)87.5 L
C)11.4 L
D)45.0 L
E)58.6 L

Question 17

How many moles of CO are contained in a 5.00 L tank at 155°C and 2.80 atm?

A)0.399 moles
B)1.10 moles
C)2.51 moles
D)0.455 moles
E)0.289 moles

Question 18

A syringe initially holds a sample of gas with a volume of 285 mL at 355 K and 1.88 atm.To what temperature must the gas in the syringe be heated/cooled in order to have a volume of 435 mL at 2.50 atm?

A)139 K
B)572 K
C)175 K
D)466 K
E)721 K

Question 19

A sample of gas initially has a volume of 859 mL at 565 K and 2.20 atm.What pressure will the sample have if the volume changes to 268 mL while the temperature is increased to 815 K?

A)10.2 atm
B)9.83 atm
C)15.3 atm
D)6.53 atm
E)1.05 atm

Question 20

What volume (in mL)will a sample of F₂ gas occupy in a syringe at 5.5 atm,if the F₂ has a volume of 25.0 mL at 1.2 atm?

A)11 mL
B)17 mL
C)3.8 mL
D)5.5 mL
E)7.6 mL

Question 21

A 0.334 g sample of an unknown halogen occupies 109 mL at 398 K and 1.41 atm.What is the identity of the halogen?

A)Br₂
B)F₂
C)Cl₂
D)I₂
E)Ge

Question 22

Determine the density of CO₂ gas at STP.

A)1.96 g/L
B)1.80 g/L
C)2.24 g/L
D)4.46 g/L
E)5.10 g/L

Question 23

A compound is found to be 30.45% N and 69.55 % O by mass.If 1.63 g of this compound occupy 389 mL at 0.00°C and 775 mm Hg,what is the molecular formula of the compound?

A)NO₂
B)N₂O
C)N₄O₂
D)N₂O₅
E)N₂O₄

Question 24

A mixture of 0.220 moles CO,0.350 moles H₂ and 0.640 moles He has a total pressure of 2.95 atm.What is the pressure of CO?

A)1.86 atm
B)0.649 atm
C)0.536 atm
D)1.54 atm
E)0.955 atm

Question 25

Which of the following gas samples would be most likely to behave ideally under the stated conditions?

A)Ne at STP
B)CO at 200 atm and 25°C
C)SO₂ at 2 atm and 0 K
D)N₂ at 1 atm and -70°C
E)O₂ at 400 atm and 25°C

Question 26

Determine the density of NH₃ gas at 435 K and 1.00 atm.

A)2.10 g/L
B)0.477 g/L
C)0.321 g/L
D)2.24 g/L
E)0.851 g/L

Question 27

What is the mole fraction of CO in a container with a H₂ mole fraction of 0.22 and an O₂ mole fraction of 0.58?

A)0.20
B)0.30
C)0.10
D)0.50

Question 28

Which of the following samples will have the lowest pressure if they are all at the same temperature and in identical containers (same V)?

A)15 g F₂
B)15 g Ne
C)15 g Kr
D)15 g CO₂
E)All of these samples will have the same pressure.

Question 29

Which of the following samples will have the greatest volume at STP?

A)22 g CO
B)22 g He
C)22 g O₂
D)22 g Cl₂
E)All of these samples would have the same volume at STP.

Question 30

A mixture of N₂,O₂ and Ar has mole fractions of 0.25,0.65,and 0.10,respectively.What is the pressure of N₂ if the total pressure of the mixture is 3.9 atm?

A)2.5 atm
B)0.39 atm
C)0.67 atm
D)0.98 atm
E)1.33 atm

Question 31

Using the graph below,determine the gas that has the lowest density at STP.

A)A
B)B
C)C
D)D
E)All of the gases have the same density at STP.

Question 32

What volume will 0.780 moles of He occupy at STP?

A)22.4 L
B)70.0 L
C)43.7 L
D)17.5 L
E)15.6 L

Question 33

A mixture of 1.0 mol He and 1.0 mol Ne are at STP in a rigid container.Which of the following statements is true?

A)Both gases have the same average kinetic energy.
B)Both gases contribute equally to the density of the mixture under these conditions.
C)Both gases have the same molecular speed.
D)The mixture has a volume of 22.4 L.
E)All of the above are true.

Question 34

A mixture of 0.220 moles CO,0.350 moles H₂ and 0.640 moles He has a total pressure of 2.95 atm.What is the pressure of H₂?

A)1.17 atm
B)0.853 atm
C)1.03 atm
D)0.969 atm
E)0.649 atm

Question 35

The density of a gas is 1.43 g/mole at STP.What is the gas?

A)Cl₂
B)S
C)O₂
D)Ne

Question 36

Which of the following samples has the greatest density at STP?

A)NO₂
B)Xe
C)SO₂
D)SF₆
E)All of these samples have the same density at STP.

Question 37

A mixture of He,Ne and Ar has a pressure of 7.85 atm.If the Ne has a mole fraction of 0.47 and Ar has a mole fraction of 0.23,what is the pressure of He?

A)4.2 atm
B)3.7 atm
C)1.8 atm
D)5.5 atm
E)2.4 atm

Question 38

Place the following gases in order of increasing density at STP.
N₂ NH₃ N₂O₄ Ar

A)N₂O₄ < Ar < N₂ < NH₃
B)Ar < N₂O₄ < N₂ < NH₃
C)N₂ < Ar < N₂O₄ < NH₃
D)NH₃ < N₂ < Ar < N₂O₄
E)Ar < N₂ < NH₃ < N₂O₄

Question 39

A 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.22 atm.What is the molar mass of the unknown compound?

A)26.3 g/mol
B)33.9 g/mol
C)12.2 g/mol
D)38.0 g/mol
E)81.8 g/mol

Question 40

What volume will 4.91 × 10²² atoms of Ne occupy at STP?

A)1.10 L
B)2.00 L
C)2.24 L
D)3.11 L
E)1.83 L

Question 41

A mixture of 10.0 g of Ne and 10.0 g Ar has a total pressure of 1.6 atm.What is the partial pressure of Ne?

A)1.1 atm
B)0.80 atm
C)0.54 atm
D)0.40 atm
E)1.3 atm

Question 42

Calculate the root mean square velocity of nitrogen molecules at 25°C.

A)729 m/s
B)515 m/s
C)149 m/s
D)297 m/s

Question 43

Rank the following in order of decreasing rate of effusion.
F₂ SF₆ CO Kr

A)SF₆ > Kr > F₂ > CO
B)Kr > CO > SF₆ > F₂
C)F₂ > Kr > CO > SF₆
D)CO > F₂ > Kr > SF₆
E)CO > F₂ > SF₆ > Kr

Question 44

Calculate the ratio of effusion rates of Cl₂ to F₂.

A)1.3661
B)0.53588
C)1.8661
D)0.28716
E)0.73204

Question 45

Identify the molecule that effuses the fastest.

A)CO
B)Ar
C)CH₄
D)CO₂

Question 46

A gas mixture contains CO,Ar and H₂.What is the total pressure of the mixture,if the mole fraction of H₂ is 0.35 and the pressure of H₂ is 0.58 atm?

A)1.7 atm
B)0.20 atm
C)0.49 atm
D)0.60 atm
E)2.1 atm

Question 47

Determine the mass of water formed when 12.5 L NH₃ (at 298 K and 1.50 atm)is reacted with 18.9 L of O₂ (at 323 K and 1.1 atm).
4 NH₃(g)+ 5 O₂(g)→ 4 NO(g)+ 6 H₂O(g)

A)17.0 g H₂O
B)20.7 g H₂O
C)37.7 g H₂O
D)13.8 g H₂O
E)27.9 g H₂O

Question 48

Which statement is true about kinetic molecular theory?

A)A single particle does not move in a straight line.
B)The size of the particle is large compared to the volume.
C)The collisions of particles with one another is completely elastic.
D)The average kinetic energy of a particle is not proportional to the temperature.

Question 49

The following reaction is used to generate hydrogen gas in the laboratory.If 243 mL of gas is collected at 25°C and has a total pressure of 745 mm Hg,what mass of hydrogen is produced? A possibly useful table of water vapor pressures is provided below.
Mg(s)+ 2 HCl(aq)→ MgCl₂(aq)+ H₂(g)T (°C)P (mm Hg)
20 17.55
25 23.78
30 31.86

A)0.0196 g H₂
B)0.0717 g H₂
C)0.0190 g H₂
D)0.0144 g H₂
E)0.0449 g H₂

Question 50

A gas mixture consists of N₂,O₂,and Ne,where the mole fraction of N₂ is 0.55 and the mole fraction of Ne is 0.25.If the mixture is at STP in a 5.0 L container,how many molecules of O₂ are present?

A)4.5 × 10²² molecules O₂
B)2.7 × 10²² molecules O₂
C)3.7 × 10²³ molecules O₂
D)1.1 × 10²³ molecules O₂
E)9.3 × 10²⁴ molecules O₂

Question 51

Determine the volume of SO₂ (at STP)formed from the reaction of 96.7 g of FeS₂ and 55.0 L of O₂ (at 398 K and 1.20 atm).The molar mass of FeS₂ is 119.99 g/mol.
4 FeS₂(s)+ 11 O₂(g)→ 2 Fe₂O₃(s)+ 8 SO₂(g)

A)36.1 L
B)45.3 L
C)18.1 L
D)27.6 L
E)32.9 L

Question 52

Determine the volume of O₂ (at STP)formed when 50.0 g of KClO₃ decomposes according to the following reaction.The molar mass for KClO₃ is 122.55 g/mol.
2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)

A)9.14 L
B)8.22 L
C)12.3 L
D)13.7 L
E)14.6 L

Question 53

Determine the theoretical yield and the percent yield if 21.8 g of K₂CO₃ is produced from reacting 27.9 g KO₂ with 29.0 L of CO₂ (at STP).The molar mass of KO₂ = 71.10 g/mol and K₂CO₃ = 138.21 g/mol.
4 KO₂(s)+ 2 CO₂(g)→ 2 K₂CO₃(s)+ 3 O₂(g)

A)27.1 g,80.4 % yield
B)179 g,12.2 % yield
C)91.7 g,23.8 % yield
D)206 g,10.6 % yield
E)61.0 g,35.7 % yield

Question 54

A gas sample contains 0.33 atm of Ne,0.45 atm of Ar,and 0.32 atm of CO.What is the total pressure?

A)1.1 atm
B)1.2 atm
C)1.0 atm
D)0.51 atm

Question 55

A syringe contains 589 mL of CO at 325 K and 1.2 atm pressure.A second syringe contains 473 mL of N₂ at 298 K and 2.6 atm.What is the final pressure if the contents of these two syringes are injected into a 1.00 L container at STP?

A)0.59 atm
B)1.1 atm
C)1.7 atm
D)1.9 atm
E)3.8 atm

Question 56

How many molecules of XeF₆ are formed from 12.9 L of F₂ (at 298 K and 2.60 atm)according to the following reaction? Assume that there is excess Xe. Xe(g)+ 3 F₂(g)→ XeF₆(g)

A)1.21 × 10²³ molecules XeF₆
B)8.25 × 10²³ molecules XeF₆
C)2.75 × 10²³ molecules XeF₆
D)7.29 × 10²³ molecules XeF₆
E)1.37 × 10²³ molecules XeF₆

Question 57

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO₂ at 398 K?

A)39.6 atm
B)7.02 atm
C)32.6 atm
D)46.6 atm
E)58.7 atm

Question 58

Determine the total pressure of all gases (at STP)formed when 50.0 mL of TNT (C₃H₅(NO₃)₃,
D = 1.60 g/mL,molar mass = 227.10 g/mol)reacts according to the following reaction.
4 C₃H₅(NO₃)₃(l)→ 6 N₂(g)+ O₂(g)+ 12 CO₂(g)+ 10 H₂O(g)

A)4.93 L
B)57.2 L
C)29.6 L
D)448 L
E)175 L

Question 59

Determine the volume of H₂S (at 375 K and 1.20 atm)needed to produce 55.0 g of S.Assume that there is excess SO₂ present.
2 H₂S(g)+ SO₂(g)→ 3 S(s)+ 2 H₂O(g)

A)44.0 L
B)29.3 L
C)22.7 L
D)34.1 L
E)66.0 L

Question 60

Which of the gases in the graph below has the largest molar mass?

A)A
B)B
C)C
D)D
E)There is not enough information to determine.

Question 61

Which of the following will cause the volume of an ideal gas to triple in value?

A)raising the temperature from 25°C to 75°C at constant pressure
B)lowering the absolute temperature by a factor of 3 at constant pressure
C)raising the absolute temperature by a factor of 3 while increasing the pressure by a factor of 3
D)lowering the absolute temperature by a factor of 3 while increasing the pressure by a factor of 3
E)lowering the pressure by a factor of 3 while the temperature stays constant

Question 62

A sample of N₂ effuses in 255 s.How long will the same size sample of Cl₂ take to effuse?

A)406 s
B)247 s
C)645 s
D)155 s
E)388 s

Question 63

Why does hot air rise?

Question 64

Why doesn't Dalton's Law of Partial Pressures depend on the identity of the gases present?

Question 65

What is the major component in dry air?

Question 66

Match the following.
Avogadro's Law

A)PV = nRT
B)V₁/n₁ = V₂/n₂
C)P_T = P_A + P_B + P_C ...
D)P₁V₁ = P₂V₂
E)V₁/T₁ = V₂/T₂

Question 67

Consider a container of gas under a particular P,V,T set of conditions.Describe how the pressure would change if the volume were doubled while the absolute temperature was doubled.

Question 68

Match the following.
Ideal Gas Law

A)PV = nRT
B)V₁/n₁ = V₂/n₂
C)P_T = P_A + P_B + P_C ...
D)P₁V₁ = P₂V₂
E)V₁/T₁ = V₂/T₂

Question 69

Match the following.
Boyle's Law

A)PV = nRT
B)V₁/n₁ = V₂/n₂
C)P_T = P_A + P_B + P_C ...
D)P₁V₁ = P₂V₂
E)V₁/T₁ = V₂/T₂

Question 70

Match the following.
Charles's Law

A)PV = nRT
B)V₁/n₁ = V₂/n₂
C)P_T = P_A + P_B + P_C ...
D)P₁V₁ = P₂V₂
E)V₁/T₁ = V₂/T₂

Question 71

Define diffusion.

Question 72

Which of the following statements is true?

A)Particles of different masses have the same average speed at a given temperature.
B)The larger a molecule,the faster it will effuse.
C)At very high pressures,a gas will occupy a larger volume than predicted by the ideal gas law.
D)For a given gas,the lower the temperature,the faster it will effuse.
E)None of the above statements are true.

Question 73

Match the following.
Dalton's Law

A)PV = nRT
B)V₁/n₁ = V₂/n₂
C)P_T = P_A + P_B + P_C ...
D)P₁V₁ = P₂V₂
E)V₁/T₁ = V₂/T₂

Question 74

Define effusion.

Question 75

Why does the rate of effusion increase with a decrease in the molar mass?

Question 76

Explain what the term "mean free path" describes.How does it change with decreasing pressure?

Question 77

The rate of effusion of oxygen to an unknown gas is 0.935.What is the other gas?

A)Ne
B)Ar
C)F₂
D)N₂

Question 78

Which of the following samples will have the greatest average speed at 355 K?

A)Ne
B)C₂H₄
C)Cl₂
D)CH₄
E)All of these samples will have the same average speed at the same temperature.

Question 79

Which of the following statements is true?

A)At a given temperature,lighter gas particles travel more slowly than heavier gas particles.
B)The smaller a gas particle,the slower it will effuse
C)The higher the temperature,the lower the average kinetic energy of the sample.
D)At low temperatures,intermolecular forces become important and the pressure of a gas will be lower than predicted by the ideal gas law.
E)None of the above statements are true.

Question 80

Which of the following compounds will behave least like an ideal gas at low temperatures?

A)He
B)SO₂
C)H₂
D)N₂
E)F₂