Question 1

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

Accepted Answer

A) He 
B) SO2 
C) H2 
D) N2 
E) F2 
A) He 
B) SO2 
C) H2 
D) N2 
E) F2

Question 2

How many mL of O2 gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.300 grams of KClO3(s)according to the chemical equation shown below?
2 KClO3(s)→ 2 KCl(s)+ 3 O2(g)

Accepted Answer

A) 30.1 mL 
B) 40.2 mL 
C) 90.4 mL 
D) 181 mL 
A) 30.1 mL 
B) 40.2 mL 
C) 90.4 mL 
D) 181 mL

Question 3

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

Accepted Answer

The rate of effusion depends o

Question 4

A sample of nitrogen gas at 25°C has a pressure of 200 torr.If the volume of the container is increased by a factor of two,what will happen to the pressure? You may assume the temperature remains constant.

Accepted Answer

A) The pressure will increase by a factor of two. 
B) The pressure will decrease by a factor of two. 
C) The pressure will not change. 
D) The pressure will decrease,but not by a factor of two. 
A) The pressure will increase by a factor of two. 
B) The pressure will decrease by a factor of two. 
C) The pressure will not change. 
D) The pressure will decrease,but not by a factor of two.

Question 5

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

Accepted Answer

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

Question 6

The mole fraction of oxygen in dry air near sea level is 0.20948.The concentration of oxygen is ________ molecules per liter,assuming an atmospheric pressure of 739 torr and a temperature of 29.5°C.

Accepted Answer

A) 6.23 
B) 0.00819 
C) 4.93 × 1021 
D) 3.75 × 1024 
E) 5.07 × 1022 
A) 6.23 
B) 0.00819 
C) 4.93 × 1021 
D) 3.75 × 1024 
E) 5.07 × 1022

Question 7

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

Accepted Answer

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

Question 8

How many molecules of N2 are in a 400.0 mL container at 780 mm Hg and 135°C?

Accepted Answer

A) 7.01 × 1021 molecules 
B) 7.38 × 1021 molecules 
C) 2.12 × 1022 molecules 
D) 2.23 × 1022 molecules 
A) 7.01 × 1021 molecules 
B) 7.38 × 1021 molecules 
C) 2.12 × 1022 molecules 
D) 2.23 × 1022 molecules

Question 9

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

Accepted Answer

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

Question 10

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 are 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 11

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)

Accepted Answer

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 
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 12

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

Accepted Answer

A) 3.82 g 
B) 7.64 g 
C) 15.3 g 
D) 45.6 g 
A) 3.82 g 
B) 7.64 g 
C) 15.3 g 
D) 45.6 g

Question 13

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.91 torr and a total pressure of air of 735 torr is ________ ppm.

Accepted Answer

A) 1.2 × 103 
B) 1.2 
C) 0.12 
D) 8.1 × 10-4 
E) 0.81 
A) 1.2 × 103 
B) 1.2 
C) 0.12 
D) 8.1 × 10-4 
E) 0.81

Question 14

A 1.44-g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0°C.The unknown gas is ________.

Accepted Answer

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

Question 15

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

Accepted Answer

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 
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 16

Calculate the ratio of effusion rates of Cl2 to O2.

Accepted Answer

A) 47.7 
B) 0.451 
C) 2.22 
D) 1.49 
E) 0.671 
A) 47.7 
B) 0.451 
C) 2.22 
D) 1.49 
E) 0.671

Question 17

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm?

Accepted Answer

A) N2 
B) O2 
C) Kr  
D) Rn  
A) N2 
B) O2 
C) Kr  
D) Rn

Question 18

What is the volume of 30.0 g of argon gas at 157°C and 2.50 kPa pressure?

Accepted Answer

A) 3.87 L 
B) 10.6 L 
C) 393 L 
D) 1070 L 
A) 3.87 L 
B) 10.6 L 
C) 393 L 
D) 1070 L

Question 19

How many liters of oxygen gas can be produced at STP from the decomposition of 0.250 L of 3.00 M H2O2 in the reaction according to the chemical equation shown below?
2 H2O2(l)→ 2 H2O(l)+ O2(g)

Accepted Answer

A) 8.41 L 
B) 11.2 L 
C) 16.8 L 
D) 33.6 L 
A) 8.41 L 
B) 11.2 L 
C) 16.8 L 
D) 33.6 L

Question 20

A steel bottle contains argon gas at STP.What is the final pressure if the temperature is changed to 145°C?

Accepted Answer

A) 0.653 atm 
B) 0.713 atm 
C) 1.40 atm 
D) 1.53 atm 
A) 0.653 atm 
B) 0.713 atm 
C) 1.40 atm 
D) 1.53 atm

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

How many mL of O₂ gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.300 grams of KClO₃(s)according to the chemical equation shown below? 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)

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

A sample of nitrogen gas at 25°C has a pressure of 200 torr.If the volume of the container is increased by a factor of two,what will happen to the pressure? You may assume the temperature remains constant.

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

The mole fraction of oxygen in dry air near sea level is 0.20948.The concentration of oxygen is ________ molecules per liter,assuming an atmospheric pressure of 739 torr and a temperature of 29.5°C.

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

How many molecules of N₂ are in a 400.0 mL container at 780 mm Hg and 135°C?

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

Which of the following statements is true?

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)

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

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.91 torr and a total pressure of air of 735 torr is ________ ppm.

A 1.44-g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0°C.The unknown gas is ________.

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

Calculate the ratio of effusion rates of Cl₂ to O₂.

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm?

What is the volume of 30.0 g of argon gas at 157°C and 2.50 kPa pressure?

How many liters of oxygen gas can be produced at STP from the decomposition of 0.250 L of 3.00 M H₂O₂ in the reaction according to the chemical equation shown below? 2 H₂O₂(l)→ 2 H₂O(l)+ O₂(g)

A steel bottle contains argon gas at STP.What is the final pressure if the temperature is changed to 145°C?

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Exam 5: Gases

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

How many mL of O2 gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.300 grams of KClO3(s)according to the chemical equation shown below? 2 KClO3(s)→ 2 KCl(s)+ 3 O2(g)

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

A sample of nitrogen gas at 25°C has a pressure of 200 torr.If the volume of the container is increased by a factor of two,what will happen to the pressure? You may assume the temperature remains constant.

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

The mole fraction of oxygen in dry air near sea level is 0.20948.The concentration of oxygen is ________ molecules per liter,assuming an atmospheric pressure of 739 torr and a temperature of 29.5°C.

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

How many molecules of N2 are in a 400.0 mL container at 780 mm Hg and 135°C?

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

Which of the following statements is true?

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)

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

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.91 torr and a total pressure of air of 735 torr is ________ ppm.

A 1.44-g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0°C.The unknown gas is ________.

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

Calculate the ratio of effusion rates of Cl2 to O2.

Which of the following would have a density of 1.37 g/L at 7.0°C and 0.987 atm?

What is the volume of 30.0 g of argon gas at 157°C and 2.50 kPa pressure?

How many liters of oxygen gas can be produced at STP from the decomposition of 0.250 L of 3.00 M H2O2 in the reaction according to the chemical equation shown below? 2 H2O2(l)→ 2 H2O(l)+ O2(g)

A steel bottle contains argon gas at STP.What is the final pressure if the temperature is changed to 145°C?

Matter, Measurement, and Problem Solving

Atoms and Elements

Molecules, Compounds and Chemical Equations

Chemical Quantities and Aqueous Reactions

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

Liquids, Solids, and Intermolecular Forces

Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Free Energy and Thermodynamics

Electrochemistry

Radioactivity and Nuclear Chemistry

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How many mL of O₂ gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.300 grams of KClO₃(s)according to the chemical equation shown below? 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)

How many molecules of N₂ are in a 400.0 mL container at 780 mm Hg and 135°C?

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

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)

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

Calculate the ratio of effusion rates of Cl₂ to O₂.

How many liters of oxygen gas can be produced at STP from the decomposition of 0.250 L of 3.00 M H₂O₂ in the reaction according to the chemical equation shown below? 2 H₂O₂(l)→ 2 H₂O(l)+ O₂(g)