AP Chemistry Review Questions - Gases and Gas Laws

You have two samples of the same gas in the same size container, at the same pressure. The temperature in the first container is -23°C and the temperature in the second container is 227°C. What is the ratio of the number of moles of gas in the first container compared to that in the second container?
1. 1:4
2. 4:1
3. 1:1
4. 2:1
5. 1:2
The tires on Mr. Allan's road bike can handle a pressure of 150 psi. What is this pressure in mm Hg? (By the way, these are very expensive tires. Don't do this on your bike at home...or your car!)
1. 775 mm Hg
2. 7.76 x 10³ mm Hg
3. 10.2 mm Hg
4. 1470 mm Hg
5. 760 mm Hg
Which flask contains the greatest number of molecules?
1. Flask 1 (NH₃)
2. Flask 2 (CH₄)
3. Flask 3 (O₂)
4. Flasks 2 and 3
5. All are the same
In which flask do the molecules have the highest average velocity?
1. Flask 1 (NH₃)
2. Flask 2 (CH₄)
3. Flask 3 (O₂)
4. Flasks 2 and 3
5. All are the same
Flask(s) ____________________ is/are most likely to exhibit ideal behavior because ______________________________.
1. Flask 3 (O₂) because it has the greatest molar mass.
2. Flask 1 (NH₃) because it has the lowest molar mass.
3. Flask 1 (NH₃) because ammonia is a polar molecule.
4. Flask 2 (CH₄) because it is a hydrocarbon.
5. Flask 2 and flask 3 because methane and oxygen are nonpolar molecules.
A motorist fills his car tires to 32 lb/in² pressure at a temperature of 30°C. Assuming no change in volume, what will the pressure in the tires be when the motorist drives across Death Valley, with a pavement temperature of 78°C?
1. 83 lb/in²
2. 28 lb/in²
3. 12 lb/in²
4. 37 lb/in²
5. 4.8 lb/in²
An 8.25 L sample of oxygen is collected at 25°C and 1.022 atm pressure. What volume will the gas occupy .940 atm and -15°C?
1. 7.77 L
2. 8.76 L
3. 10.4 L
4. 5.00 L
5. 1.78 L
A valve separates two tanks, one containing 7.6 liters of oxygen at 4.0 atmospheres and the other containing 4.0 liters of carbon dioxide at 11.0 atm. When the valve is opened and the two gases are allowed to come together, what is final pressure?
1. 3.6 atm
2. 9.5 atm
3. 6.4 atm
4. 1.8 atm
5. 8.2 atm
2.50 moles of nitrogen gas is placed in a closed 3.00 liter container at 25°C. If the temperature in the container is raised to 120°C, what will be the change in pressure?
1. 20.4 atm
2. 26.9 atm
3. 12.0 atm
4. 6.5 atm
5. 4.2 atm
The mass of 2.37 liters of a gas is 8.91 grams. What is the density of the gas?
1. 0.266 g/L
2. 3.76 g/L
3. 21.1 g/L
4. 6.54 g/L
5. None of these
325 mL of a gas at STP has a mass of .805 grams. What is the molar mass of the gaseous compound?
1. 55.5 g/mol
2. 0.0555 g/mol
3. 9.04 g/mol
4. 31.7 g/mol
5. None of these
Nitrogen has a molar mass of 28.02 g/mol. What is the density of nitrogen at 1.05 atm and 37°C?
1. 2.82 g/L
2. 1.25 g/L
3. 0.89 g/L
4. 4.72 g/cm³
5. None of these
What is the ratio of the effusion rates of O₂ and SO₂?
1. 0.50
2. 2.0
3. 1.4
4. 0.71
5. None of these
An unknown gas ("A") diffuses at 1.25 times the rate of carbon dioxide at identical conditions of pressure and temperature. What is the molar mass of gas "A"?
1. 64 g/mol
2. 52.2 g/mol
3. 14.0 g/mol
4. 22.0 g/mol
5. 28.2 g/mol
At a temperature of 250K, the molecules of an unknown gas, Z, have an average velocity equal to that of HI at 500K. What is the identity of the gas?
1. NO₂
2. CO₂
3. O₂
4. N₂
5. SO₂
You are given a 1.00-g sample of a dry gas that occupies 1.00 liter at a pressure of 545 Torr and a temperature of 25°C. The sample is bubbled through water at 35°C and collected over water so that the total pressure is 640 Torr and the temperature is 35°C. What will be the observed volume of the wet gas?
1. 0.88 L
2. 1.19 L
3. 2.20 L
4. 0.94 L
5. .099 L
A 3.00 liter mixture of CO₂ and O₂ gas, total pressure 740 Torr and temperature 50°C, is scrubbed with a water spray at 20°C so as to dissolve all the CO₂ and remove it from the gas phase. If the final observed gas volume at 740 Torr and 20°C is 2.50 liters, what percent of the molecules in the original mixture must have been CO₂? Assume that the vapor pressure of water at 20°C is 17.55 mm Hg.
1. 8.2%
2. 10.2%
3. 18.6%
4. 28.1%
5. 50%
How big a volume of dry oxygen gas at STP would you need to take to get the same number of oxygen molecules as there are hydrogen molecules in 25.0 liters at 0.850 atm and 35°C
1. 4.2 L
2. 0.068 L
3. 18.8 L
4. 0.656 L
5. 32.3 L
How many moles of gas would it take to fill an average man's lungs, total capacity of which is about 4.5 liters? Assume 1.00 atm pressure and 37.0°C.
1. 1.24 mol
2. 0.177 mol
3. 1.48 mol
4. 5.65 mol
5. 37.0 mol
A 268 cm³ sample of an ideal gas at 18°C and 748 Torr pressure is placed in an evacuated container of volume 648cm³. To what centigrade temperature must the assembly be heated so that the gas will fill the whole chamber at 748 Torr?
1. 704°C
2. 431°C
3. 597°C
4. 324°C
5. 120°C