Question 1

According to kinetic-molecular theory, if the temperature of a gas is raised from 100 °C to 200 °C, the average kinetic energy of the gas will ________.

Accepted Answer

A) double 
B) increase by a factor of 1.27 
C) increase by a factor of 100 
D) decrease by half 
E) decrease by a factor of 100 
A) double 
B) increase by a factor of 1.27 
C) increase by a factor of 100 
D) decrease by half 
E) decrease by a factor of 100

Question 2

A sample of oxygen gas (O2)was found to effuse at a rate equal to three times that of an unknown gas. The molecular weight of the unknown gas is ________ g/mol.

Accepted Answer

A) 288 
B) 96 
C) 55 
D) 4 
E) 10.7 
A) 288 
B) 96 
C) 55 
D) 4 
E) 10.7

Question 3

The density of HCN is ________ g/L at STP.

Accepted Answer

A) 1.21 
B) 329 
C) 605 
D) 0.829 
E) 2.21 
A) 1.21 
B) 329 
C) 605 
D) 0.829 
E) 2.21

Question 4

The volume of 0.25 mol of a gas at 72.7 kPa and 15 °C is ________ m3.

Accepted Answer

A) 8.1 × 10-5 
B) 1.2 × 10-4 
C) 4.3 × 10-4 
D) 8.2 × 10-3 
E) 2.2 × 10-1 
A) 8.1 × 10-5 
B) 1.2 × 10-4 
C) 4.3 × 10-4 
D) 8.2 × 10-3 
E) 2.2 × 10-1

Question 5

"Isothermal" means ________.

Accepted Answer

A) at constant pressure 
B) at constant temperature 
C) at variable temperature and pressure conditions 
D) at ideal temperature and pressure conditions 
E) that ΔHrxn = 0 
A) at constant pressure 
B) at constant temperature 
C) at variable temperature and pressure conditions 
D) at ideal temperature and pressure conditions 
E) that ΔHrxn = 0

Question 6

A gas originally at 27 °C and 1.00 atm pressure in a 3.3 L flask is cooled at constant pressure until the temperature is 11 °C. The new volume of the gas is ________ L.

Accepted Answer

A) 0.27 
B) 3.1 
C) 3.3 
D) 3.5 
E) 0.24 
A) 0.27 
B) 3.1 
C) 3.3 
D) 3.5 
E) 0.24

Question 7

The volume of fluorine gas required to react with 2.67 g of calcium bromide to form calcium fluoride and bromine at 41.0 °C and 4.31 atm is ________ mL.

Accepted Answer

A) 10.4 
B) 210 
C) 420 
D) 79.9 
E) 104 
A) 10.4 
B) 210 
C) 420 
D) 79.9 
E) 104

Question 8

A sample of He gas (2.0 mmol)effused through a pinhole in 53 s. The same amount of an unknown gas, under the same conditions, effused through the pinhole in 248 s. The molecular mass of the unknown gas is ________ g/mol.

Accepted Answer

A) 0.19 
B) 5.5 
C) 88 
D) 19 
E) 350 
A) 0.19 
B) 5.5 
C) 88 
D) 19 
E) 350

Question 9

A vessel containing Ne(g)and Ar(g)has a total pressure of 9.78. If the partial pressure of the Neon (PNe)is 3.78 and the partial pressure of the Argon (PAr)is 6, then the mole-fraction of Ne(g)is _______ and the mole-fraction of Ar(g)is ________.

Accepted Answer

A) 0.39, 0.61 
B) 0.61, 0.39 
C) 37, 58.7 
D) 0.63, 1.59 
E) 2.59, 1.63 
A) 0.39, 0.61 
B) 0.61, 0.39 
C) 37, 58.7 
D) 0.63, 1.59 
E) 2.59, 1.63

Question 10

A 0.333-g sample of an unknown pure gas occupies a volume of 0.255 L at a pressure of 1.00 atm and a temperature of 100.0 °C. The unknown gas is ________.

Accepted Answer

A) xenon 
B) neon 
C) krypton 
D) helium 
E) argon 
A) xenon 
B) neon 
C) krypton 
D) helium 
E) argon

Question 11

Using the van der Waals equation, the pressure in a 22.4 L vessel containing 1.00 mol of neon gas at   is ________ atm. (a = 0.211 L2-atm/mol2, b = 0.0171 L/mol)

Accepted Answer

A) 0.730 
B) 1.00 
C) 1.21 
D) 1.37 
E) 0.367 
A) 0.730 
B) 1.00 
C) 1.21 
D) 1.37 
E) 0.367

Question 12

In a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is ________ if the partial pressures of He and Ne are 1.50 and 2.00 atm, respectively.

Accepted Answer

A) 0.179 
B) 0.238 
C) 0.357 
D) 0.583 
E) 0.417 
A) 0.179 
B) 0.238 
C) 0.357 
D) 0.583 
E) 0.417

Question 13

A pressure of 0.500 atm is the same as a pressure of ________ of mm Hg.

Accepted Answer

A) 193 
B) 760. 
C) 380. 
D) 29.9 
E) 33.0 
A) 193 
B) 760. 
C) 380. 
D) 29.9 
E) 33.0

Question 14

Ammonium nitrite undergoes thermal decomposition to produce only gases: NH4NO2 (s) → N2 (g) + 2H2O (g)
What volume (L)of gas is produced by the decomposition of 35.0 g of NH4NO2(s)at 525 °C and 1.5 atm?

Accepted Answer

A) 48 
B) 160 
C) 15 
D) 72 
E) 24 
A) 48 
B) 160 
C) 15 
D) 72 
E) 24

Question 15

The molecular weight of a gas that has a density of 6.70 g/L at STP is ________ g/mol.

Accepted Answer

A) 4.96 × 102 
B) 1.50 × 102 
C) 7.30 × 101 
D) 3.35 
E) 2.98 × 10-1 
A) 4.96 × 102 
B) 1.50 × 102 
C) 7.30 × 101 
D) 3.35 
E) 2.98 × 10-1

Question 16

According to the kinetic-molecular theory, molecules of different gases at the same temperature always have the same average kinetic energy.

Accepted Answer

A) True 
 B)False

Question 17

Calcium hydride (CaH2)reacts with water to form hydrogen gas: CaH2 (s) + 2H2O (l) → Ca(OH)2 (aq) + 2H2 (g)
How many grams of CaH2 are needed to generate 48.0 L of H2 gas at a pressure of 0.995 atm and a temperature of 32 °C?

Accepted Answer

A) 56.8 
B) 0.954 
C) 161 
D) 40.1 
E) 80.3 
A) 56.8 
B) 0.954 
C) 161 
D) 40.1 
E) 80.3

Question 18

At 333 K, which of the pairs of gases below would have the most nearly identical rates of effusion?

Accepted Answer

A) N2O and NO2 
B) CO and N2 
C) N2 and O2 
D) CO and CO2 
E) NO2 and N2O4 
A) N2O and NO2 
B) CO and N2 
C) N2 and O2 
D) CO and CO2 
E) NO2 and N2O4

Question 19

Sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas: NaH (s) + H2O (l) → NaOH (aq) + H2 (g)
A sample of NaH weighing ________ g will produce 982 mL of gas at 28.0 °C and 765 torr, when the hydrogen is collected over water. The vapor pressure of water at this temperature is 28 torr.

Accepted Answer

A) 2.93 
B) 0.960 
C) 0.925 
D) 0.0388 
E) 925 
A) 2.93 
B) 0.960 
C) 0.925 
D) 0.0388 
E) 925

Question 20

A sample of a gas originally at 29 °C and 1.25 atm pressure in a 3.0 L container is allowed to contract until the volume is 2.2 L and the temperature is 11 °C. The final pressure of the gas is ________ atm.

Accepted Answer

A) 2.9 
B) 2.8 
C) 1.6 
D) 2.1 
E) 0.38 
A) 2.9 
B) 2.8 
C) 1.6 
D) 2.1 
E) 0.38

Exam 10: Gases

According to kinetic-molecular theory, if the temperature of a gas is raised from 100 °C to 200 °C, the average kinetic energy of the gas will ________.

A sample of oxygen gas (O2)was found to effuse at a rate equal to three times that of an unknown gas. The molecular weight of the unknown gas is ________ g/mol.

The density of HCN is ________ g/L at STP.

The volume of 0.25 mol of a gas at 72.7 kPa and 15 °C is ________ m3.

"Isothermal" means ________.

A gas originally at 27 °C and 1.00 atm pressure in a 3.3 L flask is cooled at constant pressure until the temperature is 11 °C. The new volume of the gas is ________ L.

The volume of fluorine gas required to react with 2.67 g of calcium bromide to form calcium fluoride and bromine at 41.0 °C and 4.31 atm is ________ mL.

A sample of He gas (2.0 mmol)effused through a pinhole in 53 s. The same amount of an unknown gas, under the same conditions, effused through the pinhole in 248 s. The molecular mass of the unknown gas is ________ g/mol.

A vessel containing Ne(g)and Ar(g)has a total pressure of 9.78. If the partial pressure of the Neon (PNe)is 3.78 and the partial pressure of the Argon (PAr)is 6, then the mole-fraction of Ne(g)is _______ and the mole-fraction of Ar(g)is ________.

A 0.333-g sample of an unknown pure gas occupies a volume of 0.255 L at a pressure of 1.00 atm and a temperature of 100.0 °C. The unknown gas is ________.

Using the van der Waals equation, the pressure in a 22.4 L vessel containing 1.00 mol of neon gas at is ________ atm. (a = 0.211 L2-atm/mol2, b = 0.0171 L/mol)

In a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is ________ if the partial pressures of He and Ne are 1.50 and 2.00 atm, respectively.

A pressure of 0.500 atm is the same as a pressure of ________ of mm Hg.

Ammonium nitrite undergoes thermal decomposition to produce only gases: NH4NO2 (s) → N2 (g) + 2H2O (g) What volume (L)of gas is produced by the decomposition of 35.0 g of NH4NO2(s)at 525 °C and 1.5 atm?

The molecular weight of a gas that has a density of 6.70 g/L at STP is ________ g/mol.

According to the kinetic-molecular theory, molecules of different gases at the same temperature always have the same average kinetic energy.

Calcium hydride (CaH2)reacts with water to form hydrogen gas: CaH2 (s) + 2H2O (l) → Ca(OH)2 (aq) + 2H2 (g) How many grams of CaH2 are needed to generate 48.0 L of H2 gas at a pressure of 0.995 atm and a temperature of 32 °C?

At 333 K, which of the pairs of gases below would have the most nearly identical rates of effusion?

A sample of a gas originally at 29 °C and 1.25 atm pressure in a 3.0 L container is allowed to contract until the volume is 2.2 L and the temperature is 11 °C. The final pressure of the gas is ________ atm.

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

Filters

A sample of oxygen gas (O₂)was found to effuse at a rate equal to three times that of an unknown gas. The molecular weight of the unknown gas is ________ g/mol.

The volume of 0.25 mol of a gas at 72.7 kPa and 15 °C is ________ m³.

A vessel containing Ne(g)and Ar(g)has a total pressure of 9.78. If the partial pressure of the Neon (P_Ne)is 3.78 and the partial pressure of the Argon (P_Ar)is 6, then the mole-fraction of Ne(g)is _ and the mole-fraction of Ar(g)is __.

Using the van der Waals equation, the pressure in a 22.4 L vessel containing 1.00 mol of neon gas at is ________ atm. (a = 0.211 L²-atm/mol², b = 0.0171 L/mol)

Ammonium nitrite undergoes thermal decomposition to produce only gases: NH₄NO₂ (s) → N₂ (g) + 2H₂O (g) What volume (L)of gas is produced by the decomposition of 35.0 g of NH₄NO₂(s)at 525 °C and 1.5 atm?

Calcium hydride (CaH₂)reacts with water to form hydrogen gas: CaH₂ (s) + 2H₂O (l) → Ca(OH)₂(aq) + 2H₂ (g) How many grams of CaH₂ are needed to generate 48.0 L of H₂ gas at a pressure of 0.995 atm and a temperature of 32 °C?