Question 1

A weather balloon is filled with 5.00 L of helium gas at 1.00 atm and 20°C. As it rises, the pressure drops to 0.60 atm and the temperature decreases to -10°C. What is the new volume of the balloon? (Assume ideal gas behavior.)

Accepted Answer

7.72 L

Question 2

Which of the following statements best explains why a barometer uses mercury rather than water to measure atmospheric pressure?

Accepted Answer

Mercury is denser than water, so the column needed to balance atmospheric pressure is much shorter and more practical.

Question 3

A sample of nitrogen gas occupies 10.0 L at 2.00 atm. If the pressure is reduced to 1.00 atm at constant temperature, what will be the new volume?

Accepted Answer

20.0 L

Question 4

A tire is inflated to a pressure of 32.0 psi. What is this pressure in atmospheres? (1 atm = 14.7 psi)

Accepted Answer

2.18 atm

Question 5

A 2.00 L container holds 0.082 mol of oxygen gas at 300 K. What is the pressure inside the container? (R = 0.0821 L·atm/mol·K)

Accepted Answer

1.00 atm

Question 6

A scuba diver’s tank contains air at a pressure of 200 atm in a 12.0 L tank at 27°C. How many moles of air are in the tank? (R = 0.0821 L·atm/mol·K)

Accepted Answer

96.0 mol

Question 7

Which of the following best describes Avogadro’s Law?

Accepted Answer

At constant temperature and pressure, the volume of a gas is directly proportional to the number of moles.

Question 8

A sample of methane gas has a volume of 38 mL at 5°C. If it is heated to 86°C at constant pressure, what is its new volume?

Accepted Answer

49 mL

Question 9

A hospital stores oxygen at 3000 torr in a steel cylinder. What is this pressure in atmospheres?

Accepted Answer

3.95 atm

Question 10

A 1.00 L flask contains 0.0400 mol of CO2 at 27°C. What is the pressure in the flask? (R = 0.0821 L·atm/mol·K)

Accepted Answer

0.98 atm

Question 11

A gas sample is collected over water at 25°C and a total pressure of 755 mmHg. The vapor pressure of water at 25°C is 24 mmHg. What is the partial pressure of the dry gas?

Accepted Answer

731 mmHg

Question 12

Which of the following scenarios best illustrates Boyle’s Law in a real-world context?

Accepted Answer

A syringe plunger is pushed in, decreasing the volume and increasing the pressure of the trapped air.

Question 13

A 5.00 L sample of gas at 1.00 atm and 273 K is compressed to 2.50 L and heated to 546 K. What is the final pressure?

Accepted Answer

4.00 atm

Question 14

Which of the following is NOT a correct conversion for standard pressure?

Accepted Answer

1 atm = 760 Pa

Question 15

A chemical reaction produces 0.25 mol of nitrogen gas at 1.00 atm and 25°C. What volume will the gas occupy? (R = 0.0821 L·atm/mol·K)

Accepted Answer

6.15 L

Question 16

A gas occupies 3.00 L at 25°C and 1.00 atm. If the temperature is increased to 100°C and the pressure is increased to 2.00 atm, what is the new volume?

Accepted Answer

1.73 L

Question 17

A sample of argon gas at 1.20 atm and 300 K occupies 2.50 L. If the number of moles is doubled at constant temperature and pressure, what will be the new volume?

Accepted Answer

5.00 L

Question 18

Which of the following best explains why temperature must be in Kelvin for gas law calculations?

Accepted Answer

Kelvin is an absolute scale, so zero Kelvin corresponds to zero kinetic energy, making proportional relationships valid.

Question 19

A 10.0 L tank contains 2.00 mol of hydrogen gas at 300 K. What is the pressure in the tank? (R = 0.0821 L·atm/mol·K)

Accepted Answer

4.92 atm

Question 20

A gas sample at 1.00 atm and 273 K has a volume of 22.4 L. Which law or principle does this observation illustrate?

Accepted Answer

Avogadro’s Law (molar volume at STP)

Gases: Properties, Laws, and Calculations – General Chemistry Study Notes

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