Gas Laws and Partial Pressures

The video tutorial explains Dalton's Law of Partial Pressures, which states that the total pressure of a gas mixture is the sum of the pressures each gas would exert if it were alone. It covers applications like gas collection over water, where water vapor affects total pressure, and calculations involving mole fractions. A challenge question on the decomposition of N2O4 into NO2 demonstrates practical use of the law.

What does Dalton's Law of Partial Pressures state about the total pressure of a gas mixture?

• It is the product of the pressures of individual gases.

• It is the sum of the pressures each gas would exert if it were alone.

• It is the difference between the highest and lowest gas pressures.

• It is the average of the pressures of individual gases.

If you have 1 atm of helium, 3 atm of neon, 5 atm of hexane, and 0.7 atm of uranium hexafluoride, what is the total pressure of the mixture?

• 9.7 atm

• 7.7 atm

• 8.7 atm

• 10.7 atm

When collecting gas over water, why is the actual pressure of the collected gas less than the ambient pressure?

• Because the gas is denser than water.

• Because the gas reacts with water.

• Because water vapor adds to the total pressure.

• Because the gas dissolves in water.

At 25 degrees Celsius, what is the vapor pressure of water in millimeters of mercury?

• 30.0 mmHg

• 20.0 mmHg

• 25.0 mmHg

• 23.8 mmHg

How do you calculate the partial pressure of a gas in a mixture using its mole fraction?

• Subtract the mole fraction from the total pressure.

• Multiply the mole fraction by the total pressure.

• Divide the mole fraction by the total pressure.

• Add the mole fraction to the total pressure.

If the total pressure of a gas mixture is 800 torr, and the mole fraction of hydrogen is 1/20, what is the partial pressure of hydrogen?

• 60 torr

• 80 torr

• 20 torr

• 40 torr

In the decomposition of N2O4 into NO2, what is the total pressure if 12 atm of N2O4 decomposes completely?

• 18 atm

• 6 atm

• 24 atm

• 12 atm

If the yield of the N2O4 decomposition is 50%, what is the total pressure of the mixture?

• 15 atm

• 25 atm

• 10 atm

• 20 atm

What is the mole ratio of NO2 to N2O4 in the decomposition reaction?

• 3:1

• 2:1

• 1:1

• 1:2

What is the significance of a 100% yield in the decomposition of N2O4?

• No N2O4 is converted to NO2.

• Twice the amount of N2O4 is converted to NO2.

• Half of N2O4 is converted to NO2.

• All N2O4 is converted to NO2.