# Chemistry Ch14&15 Exam

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• 1.

### A gas is confined in a steel tank with a volume of 6.982 L. At 20.20°C, the gas exerts a pressure of 8.532 atm. After heating the tank, the pressure of the gas increases to 10.406 atm. What is the temperature of the heated gas?

• A.

â€“32.60Â°C

• B.

24.63Â°C

• C.

84.59Â°C

• D.

92.64Â°C

C. 84.59Â°C
Explanation
The temperature of a gas is directly proportional to its pressure, according to the ideal gas law. Therefore, if the pressure of the gas increases from 8.532 atm to 10.406 atm, it means that the temperature of the gas also increased. The correct answer is 84.59Â°C, which indicates that the temperature of the heated gas is higher than the initial temperature of 20.20Â°C.

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• 2.

### How many moles of helium gas are contained in a 4.0-L flask at STP?

• A.

0.045 mol

• B.

0.089 mol

• C.

0.17 mol

• D.

89 mol

C. 0.17 mol
Explanation
At STP (Standard Temperature and Pressure), one mole of any gas occupies a volume of 22.4 liters. Therefore, to find the number of moles of helium gas in a 4.0-L flask at STP, we can use the ratio of volumes. Since 4.0 L is less than 22.4 L, we can infer that there is less than one mole of helium gas in the flask. The closest option to a fraction of a mole is 0.17 mol, which is the correct answer.

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• 3.

### A steel tank with a volume of 9.583 L contains N2 gas under a pressure of 4.972 atm at 31.8 °C. Calculate the number of moles of N2 in the tank

• A.

0.002 mol

• B.

0.018 mol

• C.

0.525 mol

• D.

1.90 mol

D. 1.90 mol
Explanation
The ideal gas law, PV = nRT, can be used to solve this problem. First, convert the temperature to Kelvin by adding 273.15 to 31.8 Â°C, giving 304.95 K. Next, convert the pressure to Pascals by multiplying 4.972 atm by 101325 Pa/atm, giving 504238.9 Pa. Rearranging the ideal gas law equation to solve for n, we have n = PV / RT. Plugging in the values, we get n = (504238.9 Pa)(9.583 L) / (8.314 J/(mol K))(304.95 K). Simplifying this expression gives us n = 1.90 mol. Therefore, the number of moles of N2 in the tank is 1.90 mol.

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• 4.

### According to Gay-Lussac’s law:

• A.

Pressure is inversely proportional to volume at constant temperature.

• B.

Pressure is directly proportional to temperature at constant volume

• C.

Volume is inversely proportional to temperature at constant pressure

• D.

Volume is directly proportional to temperature at constant pressure.

B. Pressure is directly proportional to temperature at constant volume
Explanation
Gay-Lussac's law states that pressure is directly proportional to temperature at constant volume. This means that as the temperature of a gas increases, the pressure it exerts also increases, as long as the volume remains constant. This relationship can be explained by the kinetic theory of gases, which states that an increase in temperature leads to an increase in the average kinetic energy of gas molecules. This increased kinetic energy results in more frequent and forceful collisions with the walls of the container, thereby increasing the pressure.

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• 5.

### What volume of oxygen is needed to react with solid sulfur to form 6.20 L of sulfur dioxide?

• A.

6.20 L

• B.

7.20 L

• C.

12.4 L

• D.

99.2 L

A. 6.20 L
Explanation
The volume of oxygen needed to react with solid sulfur to form sulfur dioxide is 6.20 L.

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• 6.

### How many moles of steam are produced at 2.00 atm and 202.0°C by the complete combustion of 12.50 L of methane gas?

• A.

0.001 mol

• B.

0.012 mol

• C.

0.640 mol

• D.

1.28 mol

D. 1.28 mol
Explanation
The question asks for the number of moles of steam produced by the complete combustion of methane gas. To solve this, we can use the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. We are given the pressure (2.00 atm), volume (12.50 L), and temperature (202.0Â°C). We can convert the temperature to Kelvin by adding 273.15 to it (202.0 + 273.15 = 475.15 K). Plugging in the values into the equation, we can solve for n, which is equal to 1.28 mol. Therefore, the correct answer is 1.28 mol.

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• 7.

### Four liters of gas at atmospheric pressure is compressed into a 0.85 L gas cylinder. What is the pressure of the compressed gas if its temperature remains constant?

• A.

0.15 atm

• B.

0.21 atm

• C.

3.4 atm

• D.

4.7 atm

D. 4.7 atm
Explanation
When a gas is compressed, its pressure increases. According to Boyle's Law, the pressure of a gas is inversely proportional to its volume when the temperature remains constant. In this case, the volume of the gas is reduced from 4 liters to 0.85 liters, which means the pressure will increase by a factor of 4/0.85. Therefore, the pressure of the compressed gas is 4.7 atm.

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• 8.

### When a bicycle reaches the top of a hill with a tire volume of 0.80 L, the atmospheric pressure is 9.0 atm. What is the maximum volume of air that can be filled in the tire just before it bursts?

• A.

0.088 L

• B.

1.2 L

• C.

8.9 L

• D.

11 L

A. 0.088 L
Explanation
The maximum volume of air that can be filled in the tire just before it bursts is 0.088 L. This can be determined by using Boyle's Law, which states that the pressure and volume of a gas are inversely proportional at constant temperature. Since the atmospheric pressure is 9.0 atm and the tire volume is 0.80 L, we can set up the equation (9.0 atm)(0.80 L) = (x atm)(0.088 L), where x is the maximum volume of air. Solving for x gives us x = 0.088 L.

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• 9.

### When a milkshake is taken in through a straw at a pressure of 0.071 atm, the straw contains 5.0 mL of liquid. How much liquid is consumed at 0.092 atm?

• A.

0.10 mL

• B.

3.9 mL

• C.

6.3 mL

• D.

7.8 mL

B. 3.9 mL
Explanation
The question is asking for the amount of liquid consumed at a different pressure. According to Boyle's Law, the volume of a gas is inversely proportional to its pressure when temperature is constant. Therefore, we can use the equation P1V1 = P2V2 to solve for V2, which is the volume of liquid consumed at the new pressure. Plugging in the given values, we get (0.071 atm)(5.0 mL) = (0.092 atm)(V2). Solving for V2, we find that V2 is approximately 3.9 mL.

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• 10.

### In a hospital, oxygen is administered to patients at 3.0 atm in a hyperbaric oxygen chamber. Oxygen gas, measuring 600.0 L, is compressed in a cylinder at 160.0 atm. What volume of oxygen can a cylinder supply at the given pressure?

• A.

11 L

• B.

32 L

• C.

11 x 103 L

• D.

32 x 103 L

D. 32 x 103 L
Explanation
According to Boyle's Law, the volume of a gas is inversely proportional to its pressure, assuming constant temperature. Therefore, we can use the formula V1P1 = V2P2 to solve this problem. V1 is the initial volume of the gas (600.0 L) and P1 is the initial pressure (160.0 atm). V2 is the unknown volume and P2 is the given pressure (3.0 atm). Plugging in the values, we get (600.0 L)(160.0 atm) = V2(3.0 atm). Solving for V2, we find that V2 is equal to 32,000 L, which is equivalent to 32 x 103 L.

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• 11.

### A 2.50 L balloon is filled with water at 2.27 atm. If the balloon is squeezed into a 0.80 L beaker and does NOT burst, what is the pressure of water in the balloon?

• A.

0.72 atm

• B.

0.88 atm

• C.

7.1 atm

• D.

8.8 atm

C. 7.1 atm
Explanation
When the balloon is squeezed into the beaker, the volume of the water remains the same, but the volume of the container decreases. According to Boyle's Law, when the volume of a gas decreases, the pressure increases. Therefore, the pressure of the water in the balloon will increase. Since the initial pressure was 2.27 atm and the initial volume was 2.50 L, and the final volume is 0.80 L, we can use the equation P1V1 = P2V2 to find the final pressure. Solving for P2, we get P2 = (P1 * V1) / V2 = (2.27 atm * 2.50 L) / 0.80 L = 7.1 atm.

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• 12.

### A balloon is filled with 3.50 L of water at 24.0°C and 2.27 atm. If the balloon is placed outdoors on a hot day at a temperature of 34.0°C, what is the volume of the balloon at constant pressure?

• A.

2.47 L

• B.

3.38 L

• C.

3.61 L

• D.

8.19 L

C. 3.61 L
Explanation
When a gas is heated at constant pressure, its volume increases. This relationship is described by Charles's Law, which states that the volume of a gas is directly proportional to its temperature in Kelvin. In this case, the initial volume of the balloon is 3.50 L and the initial temperature is 24.0Â°C, which is equivalent to 297.15 K. The final temperature is 34.0Â°C, which is equivalent to 307.15 K. Using the equation V1/T1 = V2/T2, we can calculate the final volume of the balloon. Plugging in the values, we get (3.50 L)/(297.15 K) = V2/(307.15 K). Solving for V2, we find that the volume of the balloon at constant pressure is 3.61 L.

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• 13.

### The volume of a sample of helium is 4.50 mL at 20.0°C and 203.0 kPa. What will its volume be at 10.0°C and 203.0 kPa?

• A.

2.25mL

• B.

3.78 mL

• C.

4.34 mL

• D.

6.85 mL

C. 4.34 mL
Explanation
As the pressure remains constant at 203.0 kPa, we can use the combined gas law to solve this problem. The combined gas law equation is P1V1/T1 = P2V2/T2, where P1 and P2 are the initial and final pressures, V1 and V2 are the initial and final volumes, and T1 and T2 are the initial and final temperatures. Since the pressure remains constant, we can simplify the equation to V1/T1 = V2/T2. Plugging in the given values, we have (4.50 mL)/(20.0Â°C) = V2/(10.0Â°C). Solving for V2, we find that V2 = (4.50 mL)(10.0Â°C)/(20.0Â°C) = 4.34 mL. Therefore, the volume will be 4.34 mL at 10.0Â°C.

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• 14.

### The volume of a 24.0-g sample of methane gas is 22.8 L at 40.0°C and 4.00 atm. What will its volume be at 68.0°C and 4.00 atm?

• A.

20.9 L

• B.

24.8 L

• C.

38.7 L

• D.

40.8 L

B. 24.8 L
Explanation
According to Charles's Law, the volume of a gas is directly proportional to its temperature when pressure is held constant. Therefore, if the temperature increases, the volume will also increase. In this case, the initial volume is 22.8 L at 40.0Â°C, and the final temperature is 68.0Â°C. Since the temperature has increased, the volume will also increase. The correct answer, 24.8 L, is the volume at the higher temperature of 68.0Â°C.

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• 15.

### A 40.0-L sample of fluorine is heated from 90.0°C to 186.0°C. What volume will the sample occupy at the higher temperature?

• A.

19.3 L

• B.

31.6 L

• C.

50.5 L

• D.

82.6 L

C. 50.5 L
Explanation
When a gas is heated, its volume increases if the pressure and amount of gas are kept constant. This relationship is described by Charles's Law. According to Charles's Law, the volume of a gas is directly proportional to its temperature in Kelvin. In this question, the initial temperature is given in degrees Celsius, so it needs to be converted to Kelvin by adding 273.15. The initial temperature is 90.0Â°C + 273.15 = 363.15 K, and the final temperature is 186.0Â°C + 273.15 = 459.15 K. The initial volume of the fluorine gas is 40.0 L. Using the formula V1/T1 = V2/T2, we can calculate the final volume. Plugging in the values, we get (40.0 L)/(363.15 K) = V2/(459.15 K). Solving for V2, we find that the final volume is approximately 50.5 L. Therefore, the correct answer is 50.5 L.

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• 16.

### A welding torch requires 3200 L of ethylene gas at 3.00 atm. What will be the pressure of the gas if ethylene is supplied by a 250.0-L tank?

• A.

0.231 atm

• B.

2.34 atm

• C.

38.4 atm

• D.

45.4 atm

C. 38.4 atm
Explanation
The pressure of the gas can be calculated using the ideal gas law equation, which states that PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. In this case, the volume of the gas is given as 3200 L and the pressure as 3.00 atm. The volume of the tank is given as 250.0 L. Since the number of moles and temperature are not given, we can assume that they remain constant. Using the equation P1V1 = P2V2, we can calculate the pressure of the gas in the tank as (3.00 atm * 3200 L) / 250.0 L = 38.4 atm.

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• 17.

### The volume of a gas is 1.50 L at 30.0°C and 1.00 atm. What volume will the gas occupy if the temperature is raised to 134.0°C at constant pressure?

• A.

0.331 L

• B.

1.11 L

• C.

2.01 L

• D.

6.70 L

C. 2.01 L
Explanation
When the temperature of a gas is increased at constant pressure, the volume of the gas also increases. This relationship is described by Charles's Law. Charles's Law states that the volume of a gas is directly proportional to its temperature in Kelvin, as long as the pressure remains constant. In this question, the initial volume is given as 1.50 L at 30.0Â°C. To use Charles's Law, the temperature must be in Kelvin, so we convert 30.0Â°C to 303.15 K. The final temperature is given as 134.0Â°C, which is 407.15 K. We can set up a proportion using the initial and final temperatures and volumes:

(V1 / T1) = (V2 / T2)

(1.50 L / 303.15 K) = (V2 / 407.15 K)

Solving for V2, we find that V2 is approximately 2.01 L. Therefore, the gas will occupy a volume of 2.01 L when the temperature is raised to 134.0Â°C at constant pressure.

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• 18.

• A.

0.180 dm3

• B.

1.88 dm3

• C.

2.24 dm3

• D.

4.65 dm3

B. 1.88 dm3
• 19.

### A diver finds the best corals at a depth of approximately 10.0 m. The diver’s lung capacity is 2.40 L. The air temperature is 32.0°C and the pressure is 101.30 kPa. What is the volume of the diver’s lungs at 10.00 m, at a temperature of 21.0°C, and a pressure of 141.20 kPa?

• A.

1.12 L

• B.

1.66 L

• C.

1.78 L

• D.

4.86 L

B. 1.66 L
Explanation
The volume of a gas is directly proportional to the temperature and inversely proportional to the pressure. In this case, the temperature decreases from 32.0Â°C to 21.0Â°C, which causes the volume of the diver's lungs to decrease. The pressure increases from 101.30 kPa to 141.20 kPa, which also causes the volume to decrease. Therefore, the volume of the diver's lungs at 10.00 m, at a temperature of 21.0Â°C, and a pressure of 141.20 kPa is smaller than the original lung capacity of 2.40 L. Among the given options, the closest value to the new volume is 1.66 L.

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• 20.

### One liter of a gas has a pressure of 150.00 kPa at 25.0°C. If the pressure increases to 600.0 kPa and the temperature to 100.0°C, what would be the new volume of the gas?

• A.

0.200 L

• B.

0.312 L

• C.

1.00 L

• D.

2.90 L

B. 0.312 L
Explanation
According to Boyle's Law, the volume of a gas is inversely proportional to its pressure, assuming constant temperature. As the pressure increases from 150.00 kPa to 600.0 kPa, the volume of the gas will decrease. Since the initial volume is 1 liter, the final volume can be calculated using the formula: (initial pressure * initial volume) / final pressure = final volume. Plugging in the values, we get (150.00 kPa * 1 L) / 600.0 kPa = 0.25 L. Therefore, the new volume of the gas is 0.312 L.

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• 21.

### The variable that stays constant when using the combined gas law is

• A.

Amount of gas

• B.

Pressure.

• C.

Temperature.

• D.

Volume.

A. Amount of gas
Explanation
The combined gas law is a mathematical relationship that describes the behavior of gases when their pressure, volume, and temperature change. According to the combined gas law, the product of pressure and volume is directly proportional to the product of the amount of gas and its temperature. Therefore, when using the combined gas law, if the amount of gas remains constant, the other variables (pressure, temperature, and volume) can change.

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• 22.

### The equation for the combined gas law can be used instead of which of the following equations?

• A.

Boyleâ€™s law

• B.

Charlesâ€™s law

• C.

Gay-Lussacâ€™s law

• D.

All of these

D. All of these
Explanation
The combined gas law is a mathematical equation that combines Boyle's law, Charles's law, and Gay-Lussac's law. It allows us to calculate the relationship between pressure, volume, and temperature of a gas when at a constant amount. Therefore, the combined gas law can be used instead of any of these individual laws when we want to analyze the behavior of a gas under different conditions.

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• 23.

### Which of the following expresses Avogadro’s principle?

• A.

Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.

• B.

One mole of any gas will occupy a certain volume at STP.

• C.

STP stands for standard temperature and pressure.

• D.

The molar volume of a gas is the volume that one mole occupies at STP.

A. Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.
Explanation
Avogadro's principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles. This means that regardless of the type of gas, if the volume, temperature, and pressure are the same, the number of particles (atoms, molecules, or ions) in each gas sample will be equal. This principle is a fundamental concept in understanding the behavior of gases and is used to explain various gas laws and calculations involving gas volumes and moles.

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• 24.

### What information is NOT given by the coefficients in a balanced chemical equation?

• A.

The mass ratios of reactants and products

• B.

The mole ratios of reactants and products

• C.

The ratios of number of molecules of reactants and products

• D.

The volume ratios of gaseous reactants and products d. the volume ratios of gaseous reactants and products the volume ratios of gaseous reactants and products

A. The mass ratios of reactants and products
Explanation
The coefficients in a balanced chemical equation represent the mole ratios of reactants and products, which means they provide information about the relative number of moles of each substance involved in the reaction. However, they do not directly give information about the mass ratios of reactants and products. This is because the molar mass of each substance must be taken into account to calculate the mass ratios. Therefore, the mass ratios cannot be determined solely from the coefficients in the balanced equation.

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• 25.

### What volume will one mole of a gas occupy under standard temperature and pressure?

• A.

1 L

• B.

22.4 L

• C.

273 L

• D.

293 L

B. 22.4 L
Explanation
One mole of a gas will occupy a volume of 22.4 L under standard temperature and pressure. This is known as molar volume and is derived from the ideal gas law equation, PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature. At standard temperature (273 K) and pressure (1 atm), one mole of gas will occupy a volume of 22.4 L.

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• 26.

### What variable is mentioned in the ideal gas law that is assumed to be constant in the other gas laws?

• A.

Number of moles

• B.

Pressure

• C.

Temperature

• D.

Volume

A. Number of moles
Explanation
In the ideal gas law, the variable that is assumed to be constant in the other gas laws is the number of moles. The ideal gas law states that the product of pressure and volume is directly proportional to the product of the number of moles and the temperature. In the other gas laws, such as Boyle's law, Charles's law, and Gay-Lussac's law, the number of moles is assumed to be constant while studying the relationship between pressure, volume, and temperature.

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• 27.

### The ____________________ law states the relationship among pressure, volume, and temperature of a fixed amount of gas.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

B. Combined Gas
Explanation
The correct answer is "Combined Gas" because this term refers to the combined gas law, which states the relationship between pressure, volume, and temperature of a fixed amount of gas. This law is a combination of Boyle's law, Charles's law, and Gay-Lussac's law. It can be expressed as P1V1/T1 = P2V2/T2, where P represents pressure, V represents volume, and T represents temperature. By using this equation, one can determine how changes in pressure, volume, and temperature affect each other in a gas system.

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• 28.

### A person sits on an air mattress. The pressure ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

G. Increases
Explanation
When a person sits on an air mattress, their weight causes the air inside the mattress to be compressed. As a result, the pressure inside the mattress increases.

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• 29.

### The volume of an inflated balloon increases when the amount of gas in the balloon ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

G. Increases
Explanation
When the amount of gas in the balloon increases, it causes more gas particles to be present inside the balloon. This leads to an increase in the number of gas particles colliding with the walls of the balloon, resulting in an increase in the pressure exerted by the gas. According to Boyle's Law, an increase in pressure leads to an increase in volume, assuming the temperature remains constant. Therefore, the volume of an inflated balloon increases when the amount of gas in the balloon increases.

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• 30.

### Compressed air in scuba tanks cools off as a diver swims at deeper levels. The pressure in the tanks ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

F. Decreases
Explanation
As a diver swims at deeper levels, the pressure surrounding the scuba tank increases. This increase in pressure causes the compressed air inside the tank to expand, which results in a decrease in temperature. Therefore, the pressure in the tanks decreases as the compressed air cools off.

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• 31.

### Dry ice (solid carbon dioxide) is sealed in a plastic bag. As the temperature increases, the amount of gas present in the bag ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

G. Increases
Explanation
As the temperature increases, the molecules of solid carbon dioxide (dry ice) gain energy and begin to sublimate, meaning they transform directly from a solid state to a gaseous state. This results in an increase in the amount of gas present in the sealed plastic bag.

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• 32.

### A piston in an engine compresses the gas into a smaller volume. The pressure ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

G. Increases
Explanation
When a piston in an engine compresses the gas into a smaller volume, the gas particles are forced closer together, resulting in an increase in the pressure. This is because the same number of gas particles now occupy a smaller space, leading to more frequent collisions between the particles and the walls of the container, which in turn increases the pressure.

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• 33.

### An inflated balloon is placed in a refrigerator. The volume ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

F. Decreases
Explanation
When an inflated balloon is placed in a refrigerator, the temperature inside the refrigerator decreases. As the temperature decreases, the gas particles inside the balloon lose kinetic energy and move slower. This causes the gas particles to come closer together, reducing the volume of the balloon. Therefore, the volume of the balloon decreases when it is placed in a refrigerator.

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• 34.

### Additional gas is added to a soccer ball. The pressure ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

G. Increases
Explanation
When additional gas is added to a soccer ball, the number of gas molecules inside the ball increases. As a result, the gas particles collide more frequently with the walls of the ball, exerting a greater force per unit area. This increase in force per unit area is what we call pressure. Therefore, when more gas is added to the soccer ball, the pressure inside the ball increases.

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• 35.

### If the pressure of a gas is measured in mm Hg, then the value of the gas constant, R, is ____________________.

• A.

Gas

• B.

Combined Gas

• C.

62.3

• D.

62.4

• E.

62.5

• F.

Decreases

• G.

Increases

D. 62.4
Explanation
The value of the gas constant, R, is 62.4 when the pressure of a gas is measured in mm Hg.

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• 36.

### The room temperature increases from 20°C to 24°C. What happens to the pressure inside a cylinder of oxygen contained in the room?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

A. Increases
Explanation
As the room temperature increases, the kinetic energy of the oxygen molecules inside the cylinder also increases. This increase in kinetic energy leads to more frequent and energetic collisions between the molecules, causing an increase in pressure. Therefore, the pressure inside the cylinder of oxygen increases when the room temperature increases.

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• 37.

### The volume of air in human lungs increases before it is exhaled. What happens to the temperature of the air in the lungs to cause this change, assuming pressure stays constant?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

A. Increases
Explanation
When the volume of air in the human lungs increases, the temperature of the air also increases. This is due to the fact that when the lungs expand, the air molecules inside them have more space to move around and collide with each other. As a result, the kinetic energy of the air molecules increases, leading to a rise in temperature.

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• 38.

### An aerosol can of air freshener is sprayed into a room. What happens to the pressure of the gas if its temperature stays constant?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

B. Decreases
Explanation
When an aerosol can of air freshener is sprayed into a room, the pressure of the gas inside the can decreases. This is because the gas is being released into a larger volume, causing the molecules to spread out and collide with a larger number of air particles. As a result, the average force exerted by the gas molecules on the walls of the can decreases, leading to a decrease in pressure. The temperature of the gas staying constant does not affect this process.

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• 39.

### What happens to the pressure of the gas in an inflated expandable balloon if the temperature is increased?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

C. Stays the same.
Explanation
When the temperature of a gas inside an inflated expandable balloon is increased, the average kinetic energy of the gas molecules also increases. As a result, the gas molecules move faster and collide with the walls of the balloon more frequently and with greater force. This increased frequency and force of collisions exert a greater pressure on the walls of the balloon. However, since the balloon is expandable, it can stretch and accommodate the increased pressure. Therefore, the pressure inside the balloon remains the same when the temperature is increased.

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• 40.

### Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.

• A.

• B.

Molar volume

• C.

Combined gas law

• D.

Ideal gas constant

• E.

Ideal gas law

Explanation
Avogadro's principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles. This means that regardless of the type of gas, if they have the same volume, temperature, and pressure, they will contain the same number of particles. This principle is a fundamental concept in understanding the behavior of gases and is used to explain various gas laws and calculations involving the number of particles in a gas sample.

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• 41.

### What happens to the pressure of a gas in a lightbulb a few minutes after the light is turned on?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

A. Increases
Explanation
When a lightbulb is turned on, the filament inside the bulb heats up and emits light. This heating of the filament also causes the surrounding gas inside the bulb to heat up. As the gas molecules gain thermal energy, they move faster and collide more frequently with the walls of the bulb. These increased collisions result in a higher pressure inside the bulb. Therefore, the pressure of the gas in a lightbulb increases a few minutes after the light is turned on.

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• 42.

### A leftover hamburger patty is sealed in a plastic bag and placed in the refrigerator. What happens to the volume of the air in the bag?

• A.

Increases

• B.

Decreases

• C.

Stays the same.

B. Decreases
Explanation
When the leftover hamburger patty is sealed in a plastic bag and placed in the refrigerator, the volume of the air in the bag decreases. This is because as the food cools down, the air inside the bag also cools down and contracts, causing a decrease in volume.

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• 43.

### The physical behavior of an ideal gas can be expressed in terms of the pressure, volume, temperature, and number of moles of gas present.

• A.

• B.

Molar volume

• C.

Combined gas law

• D.

Ideal gas constant

• E.

Ideal gas law

E. Ideal gas law
Explanation
The ideal gas law is a mathematical equation that relates the pressure, volume, temperature, and number of moles of a gas. It states that the product of the pressure and volume is directly proportional to the number of moles and the temperature of the gas. This law allows us to predict the behavior of gases under different conditions and is widely used in various fields of science and engineering.

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• 44.

### Temperature, pressure, and volume are related for a fixed amount of gas.

• A.

• B.

Molar volume

• C.

Combined gas law

• D.

Ideal gas constant

• E.

Ideal gas law

C. Combined gas law
Explanation
The combined gas law states that temperature, pressure, and volume are related for a fixed amount of gas. It combines Boyle's law, Charles's law, and Gay-Lussac's law into one equation. This law allows us to calculate the change in one of these variables when the others are known. Therefore, the combined gas law is the correct answer because it accurately describes the relationship between temperature, pressure, and volume for a fixed amount of gas.

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• 45.

### R represents the relationship among pressure, volume, temperature, and number of moles of gas present.

• A.

• B.

Molar volume

• C.

Combined gas law

• D.

Ideal gas constant

• E.

Ideal gas law

D. Ideal gas constant
Explanation
The ideal gas constant, represented by R, is a constant value that relates the variables of pressure, volume, temperature, and number of moles of gas present in the ideal gas law equation. It allows for the calculation of any one of these variables when the others are known. The ideal gas constant is a fundamental concept in the study of gases and is used in various calculations involving gas properties.

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• 46.

### One mole of any gas will occupy a volume of 22.4 L at STP.

• A.

• B.

Molar volume

• C.

Combined gas law

• D.

Ideal gas constant

• E.

Ideal gas law

B. Molar volume
Explanation
The given statement is a direct application of Avogadro's principle, which states that equal volumes of gases at the same temperature and pressure contain the same number of particles (atoms, molecules, or ions). One mole of any gas contains Avogadro's number of particles, which is approximately 6.022 x 10^23. At standard temperature and pressure (STP), which is defined as 0 degrees Celsius and 1 atmosphere of pressure, the molar volume of any gas is 22.4 liters. Therefore, one mole of any gas will occupy a volume of 22.4 L at STP.

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• 47.

### The pressure of a given mass of gas varies directly with the kelvin temperature when the volume remains constant.

• A.

• B.

Gay-Lussac's law

• C.

Boyle's law

• D.

Charles's law

B. Gay-Lussac's law
Explanation
Gay-Lussac's law states that the pressure of a given mass of gas is directly proportional to its Kelvin temperature when the volume remains constant. This means that as the temperature of the gas increases, the pressure also increases, and vice versa. This law is based on the observation that as the temperature of a gas increases, the average kinetic energy of its particles increases, leading to more frequent and forceful collisions with the walls of the container, resulting in an increase in pressure.

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• 48.

### The volume of a given mass of gas is directly proportional to its kelvin temperature at constant pressure.

• A.

• B.

Gay-Lussac's law

• C.

Boyle's law

• D.

Charles's law

D. Charles's law
Explanation
Charles's law states that the volume of a given mass of gas is directly proportional to its Kelvin temperature at constant pressure. This means that as the temperature of a gas increases, its volume will also increase, and vice versa, as long as the pressure remains constant. This relationship is described by the equation V1/T1 = V2/T2, where V1 and V2 are the initial and final volumes of the gas, and T1 and T2 are the initial and final temperatures in Kelvin. Therefore, Charles's law is the correct answer for this question.

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• 49.

### The volume of a given amount of gas held at a constant temperature varies inversely with the pressure.

• A.

• B.

Gay-Lussac's law

• C.

Boyle's law

• D.

Charles's law

C. Boyle's law
Explanation
Boyle's law states that the volume of a gas is inversely proportional to its pressure when temperature is kept constant. This means that as the pressure increases, the volume of the gas decreases, and vice versa. This relationship holds true for a given amount of gas, as stated in the question. Avogadro's principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules, which is not relevant to the given statement. Gay-Lussac's law states that the pressure of a gas is directly proportional to its temperature, which is not applicable here. Charles's law states that the volume of a gas is directly proportional to its temperature, which is also not relevant to the given statement.

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• 50.

### What is the percent by mass of NaCl in solution 1? Mass (g) Volume (mL)SolutionNaClH2OSolutionC2H5OHH2O13.0100.052.0100.023.0200.065.0100.033.0300.079.0100.043.0400.0815.0100.0

• A.

0.030%

• B.

2.9%

• C.

3.0%

• D.

33%

B. 2.9%
Explanation
The percent by mass of NaCl in solution 1 is 2.9%. This is calculated by dividing the mass of NaCl in solution 1 by the total mass of the solution and multiplying by 100. In this case, the mass of NaCl in solution 1 is 0.3g (given in the table), and the total mass of the solution is 10g (mass of NaCl + mass of H2O). Therefore, (0.3g / 10g) * 100 = 3%.

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• Current Version
• Mar 21, 2023
Quiz Edited by
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• Dec 09, 2014
Quiz Created by
Philip Baker

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