AP Chem Quiz: Gases

A sealed vessel contains 0.200 mol of oxygen gas, 0.100 mol of nitrogen gas, and 0.200 mol of argon gas. The total pressure of the gas mixture is 5.00 atm. The partial pressure of the argon is

• 0.200 atm

• 0.500 atm

• 1.00 atm

• 2.00 atm

The reaction between NO_(g) and O_2(g) to produce NO_2(g) in a rigid reaction vessel is represented in the diagram above. The pressure inside the container is recorded using a pressure gauge. Which of the following statements correctly predicts the change in pressure as the reaction goes to completion at constant temperature, and provides the correct explanation?

• The pressure will increase because the product molecules have a greater mass than either of the reactant molecules.

• The pressure will decrease because there are fewer molecules of product than of reactants.

• The pressure will not change because the total mass of the product molecules is the same as the total mass of the reactant molecules.

The volume of a sample of helium is 4.5 mL at 20.0°C and 203.0 kPa. What will its volume be in the figure?

• 2.25 mL

• 3.78 mL

• 4.34 mL

• 6.85 mL

At an ocean depth of 10.0 m, a 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 the same depth, at a temperature of 21.0°C and a pressure of 141.20 kPa?

• 1.12 L

• 1.66 L

• 1.78 L

• 4.86 L

What volume does .0685 mol of gas occupy at STP?

• 0.3707 mol

• 0.7515 mol

• 1.53 L

• 3.06 L

What are the values for STP?

• 0 K and 1 atm
• 0^oC and 1 atm
• 760 K and 1 atm
• 273^oC and 1 atm

1.00 mole of He was placed in each flask. Which statement is true?

• Since all flask have same amount of gas, flask 1 has the least pressure

• Since all flask have same amount of gas, flask 2 has the least pressure

• Since all flask have same amount of gas, flask 3 has the least pressure

• Since all flask have same amount of gas, flask 4 has the least pressure

Compressing a gas makes the pressure _______.

• increase
• decrease
• stay the same
• I don't know

Calculate the molar mass of a gaseous substance if 0.125 g of the gas occupies 93.3 mL at STP.

• 30.0 g/mol

• 30.2 g/mol

• 30.4g/mol

• 30.6 g/mol

• None of the above

Two sealed, rigid 5.0L containers each contain a gas at the same temperature but at a different pressure, as shown above. Also shown are the results of transferring the entire contents of container 1 to container 2. No gases escape during the transfer. Assuming ideal behavior, which statement is correct regarding the total pressure of the gases after they are combined?

• The total pressure of the gases in the mixture is the sum of the initial pressures of oxygen gas and nitrogen gas because pressure only depends on the total amount of gas when volume and temperature are held constant.

• The total pressure of the gases in the mixture is lower than the sum of the initial pressures of oxygen and nitrogen because some of the energy of the particles will be lost due to an increase in the number of collisions.

• The total pressure of the gases in the mixture is higher than the sum of the initial pressures of oxygen and nitrogen because of the intermolecular forces that develop between oxygen and nitrogen molecules.

• The total pressure of the gases in the mixture cannot be determined because the actual value of the temperature is not given.