Question 1

How many moles of gas are there in a 36.3 L container at 25.2 °C and 570.3 mm Hg?

Accepted Answer

A) 1.11 
B) 13.2 
C) 0.863 
D) 0.0110 
E) 16,700 
A) 1.11 
B) 13.2 
C) 0.863 
D) 0.0110 
E) 16,700

Question 2

Of the following, ________ is a correct statement of Boyle's law.

Accepted Answer

A) PV = constant 
B)    = constant 
C)    = constant 
D)    = constant 
E)    = constant 
A) PV = constant 
B)    = constant 
C)    = constant 
D)    = constant 
E)    = constant

Question 3

At a temperature of ________ °C, 0.444 mol of CO gas occupies 11.8 L at 839 torr.

Accepted Answer

A) 379 
B) 73.0 
C) 14.0 
D) 32.0 
E) 83.5 
A) 379 
B) 73.0 
C) 14.0 
D) 32.0 
E) 83.5

Question 4

A sample of a gas originally at 25 °C and 1.00 atm pressure in a 2.5 L container is subject to a pressure of 0.85 atm and a temperature of 15 °C. The final volume of the gas is ________ L.

Accepted Answer

A) 3.0 
B) 2.8 
C) 2.6 
D) 2.1 
E) 0.38 
A) 3.0 
B) 2.8 
C) 2.6 
D) 2.1 
E) 0.38

Question 5

The volume of fluorine gas required to react with 4.26 g of calcium bromide to form calcium fluoride and bromine at 25.0 °C and 4195 torr is ________ L.

Accepted Answer

A) 0.0943 
B) 0.241 
C) 241 
D) 1.24 × 10-4 
E) 0.124 
A) 0.0943 
B) 0.241 
C) 241 
D) 1.24 × 10-4 
E) 0.124

Question 6

If the temperature is lowered from 60 °C to 30 °C, the volume of a fixed amount of gas will be one half the original volume.

Accepted Answer

A) True 
 B)False

Question 7

A sample of gas (1.9 mol)is in a flask at 21 °C and 697 mm Hg. The flask is opened and more gas is added to the flask. The new pressure is 841 mm Hg and the temperature is now 26 °C. There are now ________ mol of gas in the flask.

Accepted Answer

A) 1.6 
B) 2.3 
C) 2.9 
D) 3.5 
E) 0.28 
A) 1.6 
B) 2.3 
C) 2.9 
D) 3.5 
E) 0.28

Question 8

The thermal decomposition of potassium chlorate can be used to produce oxygen in the laboratory. 2KClO3 (s) → 2KCl (s) + 3O2 (g)
What volume (L)of O2 gas at 25 °C and 1.00 atm pressure is produced by the decomposition of 7.5 g of KClO3 (s)?

Accepted Answer

A) 4.5 
B) 7.5 
C) 2.3 
D) 3.7 
E) 11 
A) 4.5 
B) 7.5 
C) 2.3 
D) 3.7 
E) 11

Question 9

The reaction of 100 mL of Cl2 gas with 100 mL of CH4 gas via the equation: Cl2 (g) + CH4 (g) → HCl (g) + CH3Cl (g)
Will produce a total of ________ mL of products if pressure and temperature are kept constant.

Accepted Answer

A) 100 
B) 50 
C) 200 
D) 150 
E) 250 
A) 100 
B) 50 
C) 200 
D) 150 
E) 250

Question 10

The molecular weight of a gas is ________ g/mol if 6.7 g of the gas occupies 6.3 L at STP.

Accepted Answer

A) 24 
B) 3.6 × 103 
C) 27 
D) 3.0 × 102 
E) 1.8 × 10-2 
A) 24 
B) 3.6 × 103 
C) 27 
D) 3.0 × 102 
E) 1.8 × 10-2

Question 11

An ideal gas differs from a real gas in that the molecules of an ideal gas ________.

Accepted Answer

A) have no attraction for one another 
B) have appreciable molecular volumes 
C) have a molecular weight of zero 
D) have no kinetic energy 
E) have an average molecular mass 
A) have no attraction for one another 
B) have appreciable molecular volumes 
C) have a molecular weight of zero 
D) have no kinetic energy 
E) have an average molecular mass

Question 12

Of the following, ________ has a slight odor of bitter almonds and is toxic.

Accepted Answer

A) NH3 
B) N2O 
C) CO 
D) CH4 
E) HCN 
A) NH3 
B) N2O 
C) CO 
D) CH4 
E) HCN

Question 13

Since air is a mixture, it does not have a "molar mass." However, for calculation purposes, it is possible to speak of its "effective molar mass." (An effective molar mass is a weighted average of the molar masses of a mixture's components.)If air at STP has a density of 1.285 g/L, its effective molar mass is ________ g/mol.

Accepted Answer

A) 26.94 
B) 31.49 
C) 30.00 
D) 34.42 
E) 28.80 
A) 26.94 
B) 31.49 
C) 30.00 
D) 34.42 
E) 28.80

Question 14

According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200 °C?

Accepted Answer

A) NH3 
B) N2O 
C) O2 
D) UF6 
E) None. The molecules of all gases have the same root-mean-square speed at any given temperature. 
A) NH3 
B) N2O 
C) O2 
D) UF6 
E) None. The molecules of all gases have the same root-mean-square speed at any given temperature.

Question 15

At STP, the ratio of the root-mean-square speed of CO2 to that of SO2 is ________.

Accepted Answer

A) 2.001 
B) 2.119 
C) 1.000 
D) 1.207 
E) 1.456 
A) 2.001 
B) 2.119 
C) 1.000 
D) 1.207 
E) 1.456

Question 16

Which of the following statements about gases is false?

Accepted Answer

A) Gases are highly compressible. 
B) Distances between molecules of gas are very large compared to bond distances within molecules. 
C) Non-reacting gas mixtures are homogeneous. 
D) Gases expand spontaneously to fill the container they are placed in. 
E) All gases are colorless and odorless at room temperature. 
A) Gases are highly compressible. 
B) Distances between molecules of gas are very large compared to bond distances within molecules. 
C) Non-reacting gas mixtures are homogeneous. 
D) Gases expand spontaneously to fill the container they are placed in. 
E) All gases are colorless and odorless at room temperature.

Question 17

A mixture of Xe, Kr, and Ar has a total pressure of 6.69 atm. What is the mole fraction of Kr if the partial pressures of Xe and Ar are 1.92 atm and 2.75 atm, respectively.

Accepted Answer

A) 0.302 
B) 0.287 
C) 0.411 
D) 0.259 
E) 0.698 
A) 0.302 
B) 0.287 
C) 0.411 
D) 0.259 
E) 0.698

Question 18

A real gas will behave most like an ideal gas under conditions of ________.

Accepted Answer

A) high temperature and high pressure 
B) high temperature and low pressure 
C) low temperature and high pressure 
D) low temperature and low pressure 
E) STP 
A) high temperature and high pressure 
B) high temperature and low pressure 
C) low temperature and high pressure 
D) low temperature and low pressure 
E) STP

Question 19

A sample of N2 gas (2.0 mmol)effused through a pinhole in 5.5 s. It will take ________ s for the same amount of CH4 to effuse under the same conditions.

Accepted Answer

A) 7.3 
B) 5.5 
C) 3.1 
D) 4.2 
E) 9.6 
A) 7.3 
B) 5.5 
C) 3.1 
D) 4.2 
E) 9.6

Question 20

According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200 °C?

Accepted Answer

A) HCl 
B) Cl2 
C) H2O 
D) SF6 
E) None. The molecules of all gases have the same root-mean-square speed at any given temperature. 
A) HCl 
B) Cl2 
C) H2O 
D) SF6 
E) None. The molecules of all gases have the same root-mean-square speed at any given temperature.

Exam 10: Gases

How many moles of gas are there in a 36.3 L container at 25.2 °C and 570.3 mm Hg?

Of the following, ________ is a correct statement of Boyle's law.

At a temperature of ________ °C, 0.444 mol of CO gas occupies 11.8 L at 839 torr.

A sample of a gas originally at 25 °C and 1.00 atm pressure in a 2.5 L container is subject to a pressure of 0.85 atm and a temperature of 15 °C. The final volume of the gas is ________ L.

The volume of fluorine gas required to react with 4.26 g of calcium bromide to form calcium fluoride and bromine at 25.0 °C and 4195 torr is ________ L.

If the temperature is lowered from 60 °C to 30 °C, the volume of a fixed amount of gas will be one half the original volume.

A sample of gas (1.9 mol)is in a flask at 21 °C and 697 mm Hg. The flask is opened and more gas is added to the flask. The new pressure is 841 mm Hg and the temperature is now 26 °C. There are now ________ mol of gas in the flask.

The thermal decomposition of potassium chlorate can be used to produce oxygen in the laboratory. 2KClO3 (s) → 2KCl (s) + 3O2 (g) What volume (L)of O2 gas at 25 °C and 1.00 atm pressure is produced by the decomposition of 7.5 g of KClO3 (s)?

The reaction of 100 mL of Cl2 gas with 100 mL of CH4 gas via the equation: Cl2 (g) + CH4 (g) → HCl (g) + CH3Cl (g) Will produce a total of ________ mL of products if pressure and temperature are kept constant.

The molecular weight of a gas is ________ g/mol if 6.7 g of the gas occupies 6.3 L at STP.

An ideal gas differs from a real gas in that the molecules of an ideal gas ________.

Of the following, ________ has a slight odor of bitter almonds and is toxic.

According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200 °C?

At STP, the ratio of the root-mean-square speed of CO2 to that of SO2 is ________.

Which of the following statements about gases is false?

A mixture of Xe, Kr, and Ar has a total pressure of 6.69 atm. What is the mole fraction of Kr if the partial pressures of Xe and Ar are 1.92 atm and 2.75 atm, respectively.

A real gas will behave most like an ideal gas under conditions of ________.

A sample of N2 gas (2.0 mmol)effused through a pinhole in 5.5 s. It will take ________ s for the same amount of CH4 to effuse under the same conditions.

According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200 °C?

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

Thermochemistry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Chemical Thermodynamics

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

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The thermal decomposition of potassium chlorate can be used to produce oxygen in the laboratory. 2KClO₃ (s) → 2KCl (s) + 3O₂ (g) What volume (L)of O₂ gas at 25 °C and 1.00 atm pressure is produced by the decomposition of 7.5 g of KClO₃ (s)?

The reaction of 100 mL of Cl₂ gas with 100 mL of CH₄ gas via the equation: Cl₂ (g) + CH₄ (g) → HCl (g) + CH₃Cl (g) Will produce a total of ________ mL of products if pressure and temperature are kept constant.

At STP, the ratio of the root-mean-square speed of CO₂ to that of SO₂ is ________.

A sample of N₂ gas (2.0 mmol)effused through a pinhole in 5.5 s. It will take ________ s for the same amount of CH₄ to effuse under the same conditions.