Question 1

The concentration of carbon monoxide in a sample of air is 8.1 × 10-6.There are ________ molecules of CO in 1.00 L of this air at 755 torr and 23°C.

Accepted Answer

A)  3.3 ×   
B)  2.0 ×   
C)  2.6 ×   
D)  1.5 ×   
E)  2.0 ×   
A)  3.3 ×   
B)  2.0 ×   
C)  2.6 ×   
D)  1.5 ×   
E)  2.0 ×

Question 2

In the laboratory,hydrogen gas is usually made by the following reaction: Zn(s)+ 2 HCl(aq)→ H2(g)+ ZnCl2(aq)
How many liters of H2 gas,collected over water at an atmospheric pressure of 752 mm Hg and a temperature of 21.0°C,can be made from 1.566 g of Zn and excess HCl? The partial pressure of water vapor is 18.65 mm Hg at 21.0°C.

Accepted Answer

A)  0.0428 L 
B)  0.573 L 
C)  0.585 L 
D)  0.599 L 
A)  0.0428 L 
B)  0.573 L 
C)  0.585 L 
D)  0.599 L

Question 3

What is the temperature of O3 gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s?

Accepted Answer

A)  1.44 K 
B)  1.08 × 103 K 
C)  1.44 × 103 K 
D)  1.08 × 106 K 
A)  1.44 K 
B)  1.08 × 103 K 
C)  1.44 × 103 K 
D)  1.08 × 106 K

Question 4

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

Accepted Answer

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

Question 5

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)

Accepted Answer

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

Question 6

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?

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 7

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?

Accepted Answer

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

Question 8

How many grams of water are required to produce 6.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below? BaH2(s)+ 2 H2O(l)→ Ba(OH)2(aq)+ 2 H2(g)

Accepted Answer

A)  2.38 g 
B)  4.75 g 
C)  4.81 g 
D)  9.50 g 
A)  2.38 g 
B)  4.75 g 
C)  4.81 g 
D)  9.50 g

Question 9

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?

Accepted Answer

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

Question 10

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 11

Which of the following statements is TRUE?

Accepted Answer

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 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 is true.

Question 12

Give the definition for effusion.

Accepted Answer

A)  gas molecules mix equally 
B)  gas molecules spread out in a concentration gradient 
C)  gas molecules escape from a container into a vacuum through a small hole 
D)  average distance between collisions 
E)  gas molecules mix unequally 
A)  gas molecules mix equally 
B)  gas molecules spread out in a concentration gradient 
C)  gas molecules escape from a container into a vacuum through a small hole 
D)  average distance between collisions 
E)  gas molecules mix unequally

Question 13

A gas is at 35.0°C and 2.50 L.What is the temperature of the gas if the volume is increased to 5.00 L?

Accepted Answer

A)  343°C 
B)  70.0°C 
C)  616°C 
D)  1.16°C 
E)  17.5°C 
A)  343°C 
B)  70.0°C 
C)  616°C 
D)  1.16°C 
E)  17.5°C

Question 14

A gas mixture contains Rn,He and N2.What is the total pressure of the mixture,if the mole fraction of N2 is 0.350 and the partial pressure of N2 is 0.580 atm?

Accepted Answer

A)  1.66 atm 
B)  0.203 atm 
C)  4.93 atm 
D)  0.603 atm 
E)  2.1 atm 
A)  1.66 atm 
B)  0.203 atm 
C)  4.93 atm 
D)  0.603 atm 
E)  2.1 atm

Question 15

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

Accepted Answer

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

Question 16

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.80 torr and a total pressure of air of 695 torr is ________%.

Accepted Answer

A)  1.2 ×   
B)  1.2 
C)  0.12 
D)  8.7 ×   
E)  0.87 
A)  1.2 ×   
B)  1.2 
C)  0.12 
D)  8.7 ×   
E)  0.87

Question 17

A scuba diver experiences ________ as she descends into the ocean water.

Accepted Answer

A)  decrease of 1 atm for each 15 m of depth 
B)  decrease of 1 atm for each 22 m of depth 
C)  increase of 1 atm for each 20 m of depth 
D)  increase of 1 atm for each 10 m of depth 
E)  no difference in pressure 
A)  decrease of 1 atm for each 15 m of depth 
B)  decrease of 1 atm for each 22 m of depth 
C)  increase of 1 atm for each 20 m of depth 
D)  increase of 1 atm for each 10 m of depth 
E)  no difference in pressure

Question 18

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: Zn(s)+     (aq)→ Zn   (aq)+   (g)
In an experiment,201 mL of wet   is collected over water at 27°C and a barometric pressure of   How many grams of Zn have been consumed? The vapor pressure of water at 27°C is

Accepted Answer

A)  4.18 ×   g 
B)  0.496 g 
C)  496 g 
D)  377 g 
E)  3.77 ×   g 
A)  4.18 ×   g 
B)  0.496 g 
C)  496 g 
D)  377 g 
E)  3.77 ×   g

Question 19

What is the volume of 9.783 × 1023 atoms of He at 9.25 atm and 512K?

Accepted Answer

A)  7.38 L 
B)  3.69 L 
C)  1.85 L 
D)  15.4 L 
E)  30.8 L 
A)  7.38 L 
B)  3.69 L 
C)  1.85 L 
D)  15.4 L 
E)  30.8 L

Question 20

What is the volume of 5.60 g of O2 at 7.78 atm and 415 K?

Accepted Answer

A)  1.53 L 
B)  565 L 
C)  24.5 L 
D)  25.0 L 
E)  0.766 L 
A)  1.53 L 
B)  565 L 
C)  24.5 L 
D)  25.0 L 
E)  0.766 L

Exam 5: Gases

The concentration of carbon monoxide in a sample of air is 8.1 × 10-6.There are ________ molecules of CO in 1.00 L of this air at 755 torr and 23°C.

What is the temperature of O3 gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s?

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

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 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?

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?

How many grams of water are required to produce 6.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below? BaH2(s)+ 2 H2O(l)→ Ba(OH)2(aq)+ 2 H2(g)

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?

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

Which of the following statements is TRUE?

Give the definition for effusion.

A gas is at 35.0°C and 2.50 L.What is the temperature of the gas if the volume is increased to 5.00 L?

A gas mixture contains Rn,He and N2.What is the total pressure of the mixture,if the mole fraction of N2 is 0.350 and the partial pressure of N2 is 0.580 atm?

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

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.80 torr and a total pressure of air of 695 torr is ________%.

A scuba diver experiences ________ as she descends into the ocean water.

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: Zn(s)+ (aq)→ Zn (aq)+ (g) In an experiment,201 mL of wet is collected over water at 27°C and a barometric pressure of How many grams of Zn have been consumed? The vapor pressure of water at 27°C is

What is the volume of 9.783 × 1023 atoms of He at 9.25 atm and 512K?

What is the volume of 5.60 g of O2 at 7.78 atm and 415 K?

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Filters

The concentration of carbon monoxide in a sample of air is 8.1 × 10^-6.There are ________ molecules of CO in 1.00 L of this air at 755 torr and 23°C.

What is the temperature of O₃ gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s?

Determine the volume of O₂ (at STP)formed when 50.0 g of KClO₃ decomposes according to the following reaction.The molar mass for KClO₃is 122.55 g/mol. 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)

How many grams of water are required to produce 6.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below? BaH₂(s)+ 2 H₂O(l)→ Ba(OH)₂(aq)+ 2 H₂(g)

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 gas mixture contains Rn,He and N₂.What is the total pressure of the mixture,if the mole fraction of N₂ is 0.350 and the partial pressure of N₂ is 0.580 atm?

What is the volume of 9.783 × 10²³ atoms of He at 9.25 atm and 512K?

What is the volume of 5.60 g of O₂ at 7.78 atm and 415 K?