Question 1

Convert 123.80 kPa to bar.

Accepted Answer

A)  1.222 bar 
B)  1.087 bar 
C)  0.8078 bar 
D)  0.9186 bar 
E)  1.238 bar 
A)  1.222 bar 
B)  1.087 bar 
C)  0.8078 bar 
D)  0.9186 bar 
E)  1.238 bar

Question 2

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

Accepted Answer

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

Question 3

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

Accepted Answer

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 
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 4

A 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.24 bar. What is the molar mass of the unknown compound?

Accepted Answer

A)  26.3 g   
B)  33.9 g   
C)  12.2 g   
D)  37.9 g   
E)  81.8 g   
A)  26.3 g   
B)  33.9 g   
C)  12.2 g   
D)  37.9 g   
E)  81.8 g

Question 5

Which of the following is FALSE?

Accepted Answer

A)  Kinetic molecular theory is a quantitative model for gases. 
B)  Kinetic molecular theory assumes that the gas particles are negligibly small. 
C)  Kinetic molecular theory assumes that the kinetic energy of the gas particles is proportional to the temperature in Kelvin. 
D)  The collisions of the gas particles are elastic. 
E)  Kinetic molecular theory assumes that the space occupied by the gas particles are significantly large. 
A)  Kinetic molecular theory is a quantitative model for gases. 
B)  Kinetic molecular theory assumes that the gas particles are negligibly small. 
C)  Kinetic molecular theory assumes that the kinetic energy of the gas particles is proportional to the temperature in Kelvin. 
D)  The collisions of the gas particles are elastic. 
E)  Kinetic molecular theory assumes that the space occupied by the gas particles are significantly large.

Question 6

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

Accepted Answer

A)  0.393 moles 
B)  1.10 moles 
C)  2.51 moles 
D)  0.455 moles 
E)  0.289 moles 
A)  0.393 moles 
B)  1.10 moles 
C)  2.51 moles 
D)  0.455 moles 
E)  0.289 moles

Question 7

The volume of a gas is inversely proportional to the pressure of a gas. What is this known as?

Accepted Answer

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

Question 8

A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mmHg. What volume of gas will the balloon contain at 1.368 bar and 253 K?

Accepted Answer

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

Question 9

Why doesn't Dalton's law of partial pressures depend on the identity of the gases present?

Accepted Answer

It is assumed that all gas particles are

Question 10

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH2(s) + 2H2O(l) → Ca(OH)2(aq) + 2H2(g)

Accepted Answer

A)  3.77 g 
B)  7.64 g 
C)  15.3 g 
D)  45.6 g 
A)  3.77 g 
B)  7.64 g 
C)  15.3 g 
D)  45.6 g

Question 11

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is ________ molecules per litre, assuming an atmospheric pressure of 0.985 bar and a temperature of 29.5 °C.

Accepted Answer

A)  6.23 
B)  0.00819 
C)  4.94 × 1021 
D)  3.75 × 1024 
E)  5.07 × 1022 
A)  6.23 
B)  0.00819 
C)  4.94 × 1021 
D)  3.75 × 1024 
E)  5.07 × 1022

Question 12

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 bar?

Accepted Answer

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

Question 13

A balloon filled with helium gas at 20 °C occupies 4.91 L at 1.00 atm. The balloon is immersed in liquid nitrogen at -196 °C, while the pressure is raised to 5.20 atm. What is the volume of the balloon in the liquid nitrogen?

Accepted Answer

A)  0. 25 L 
B)  3.6 L 
C)  6.7 L 
D)  97 L 
A)  0. 25 L 
B)  3.6 L 
C)  6.7 L 
D)  97 L

Question 14

What volume will 0.780 moles of He occupy at STP?

Accepted Answer

A)  22.4 L 
B)  70.0 L 
C)  43.7 L 
D)  17.7 L 
E)  15.6 L 
A)  22.4 L 
B)  70.0 L 
C)  43.7 L 
D)  17.7 L 
E)  15.6 L

Question 15

Define the vapour pressure of water.

Accepted Answer

A)  partial pressure of water in a liquid mixture 
B)  partial pressure of water in a gaseous mixture 
C)  condensation of water 
D)  water dissolved in a liquid 
E)  water molecules 
A)  partial pressure of water in a liquid mixture 
B)  partial pressure of water in a gaseous mixture 
C)  condensation of water 
D)  water dissolved in a liquid 
E)  water molecules

Question 16

Give the formula for ozone.

Accepted Answer

A)  O3 
B)  O2 
C)  O 
D)  H2O2 
E)  H2O 
A)  O3 
B)  O2 
C)  O 
D)  H2O2 
E)  H2O

Question 17

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 increasing by a factor of 2.

Accepted Answer

The pressure would stay constant. The do

Question 18

Which of the following statements is TRUE?

Accepted Answer

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 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 is true.

Question 19

Identify the gas particle that travels the slowest.

Accepted Answer

A)  H2 
B)  O2 
C)  Ne 
D)  N2 
E)  CO 
A)  H2 
B)  O2 
C)  Ne 
D)  N2 
E)  CO

Question 20

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

Accepted Answer

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

Exam 5: Gases

Convert 123.80 kPa to bar.

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

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

A 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.24 bar. What is the molar mass of the unknown compound?

Which of the following is FALSE?

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

The volume of a gas is inversely proportional to the pressure of a gas. What is this known as?

A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mmHg. What volume of gas will the balloon contain at 1.368 bar and 253 K?

Why doesn't Dalton's law of partial pressures depend on the identity of the gases present?

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH2(s) + 2H2O(l) → Ca(OH)2(aq) + 2H2(g)

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is ________ molecules per litre, assuming an atmospheric pressure of 0.985 bar and a temperature of 29.5 °C.

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 bar?

A balloon filled with helium gas at 20 °C occupies 4.91 L at 1.00 atm. The balloon is immersed in liquid nitrogen at -196 °C, while the pressure is raised to 5.20 atm. What is the volume of the balloon in the liquid nitrogen?

What volume will 0.780 moles of He occupy at STP?

Define the vapour pressure of water.

Give the formula for ozone.

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 increasing by a factor of 2.

Which of the following statements is TRUE?

Identify the gas particle that travels the slowest.

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

Units of Measurement for Physical and Chemical Change

Atoms and Elements

Molecules, Compounds, and Nomenclature

Chemical Reactions and Stoichiometry

Thermochemistry

The Quantum-Mechanical Model of the Atom

Periodic Properties of the Elements

Chemical Bonding I: Lewis Theory

Chemical Bonding Ii: Molecular Shapes, Valence Bond Theory, and Molecular Orbital Theory

Liquids, Solids, and Intermolecular Forces

Solutions

Chemical Kinetics

Chemical Equilibrium

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Gibbs Energy and Thermodynamics

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Radioactivity and Nuclear Chemistry

Organic Chemistry I: Structures

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Filters

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

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

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH₂(s) + 2H₂O(l) → Ca(OH)₂(aq) + 2H₂(g)

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 bar?

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