Basic Gas Chemistry Quiz

1. Where would molecules be farther apart?

When the substance is a gas

When the substance is a liquid

When the substance is a solid

In a gas, molecules have more freedom of movement and are not bound tightly together. This allows them to spread out and occupy a larger volume, resulting in greater distance between molecules compared to a liquid or solid. In a liquid, molecules are closer together due to intermolecular forces, while in a solid, molecules are tightly packed and have the least amount of space between them. Therefore, molecules are farther apart when the substance is a gas.

Explanation

In a gas, molecules have more freedom of movement and are not bound tightly together. This allows them to spread out and occupy a larger volume, resulting in greater distance between molecules compared to a liquid or solid. In a liquid, molecules are closer together due to intermolecular forces, while in a solid, molecules are tightly packed and have the least amount of space between them. Therefore, molecules are farther apart when the substance is a gas.

2. Which of the following changes would INCREASE the pressure of a gas in a closed container?

Increased volume of container

Increased number of particles in the container

Decreased temperature

Increasing the number of particles in the container would increase the pressure of the gas in a closed container. This is because an increase in the number of particles leads to more collisions between the gas molecules and the walls of the container, resulting in an increase in pressure.

Explanation

Increasing the number of particles in the container would increase the pressure of the gas in a closed container. This is because an increase in the number of particles leads to more collisions between the gas molecules and the walls of the container, resulting in an increase in pressure.

3. Which of the following is NOT true about gases?

Gases have an indefinite volume

Gases have less kinetic energy than the same substance as a liquid.

Gases are compressible

Gases are farther apart than liquids.

The statement "Gases have less kinetic energy than the same substance as a liquid" is not true. In fact, gases have more kinetic energy than the same substance as a liquid. Kinetic energy is the energy of motion, and gases have higher kinetic energy because their particles are moving more freely and rapidly compared to the particles in a liquid.

Explanation

The statement "Gases have less kinetic energy than the same substance as a liquid" is not true. In fact, gases have more kinetic energy than the same substance as a liquid. Kinetic energy is the energy of motion, and gases have higher kinetic energy because their particles are moving more freely and rapidly compared to the particles in a liquid.

4. Which of the following are standard pressures:
I: 1 atomosphere
II 760 mm Hg
III.100 mm Hg
IV. 100 kPa
V. 101.3 kPa
VI: 1 mm Hg

I, II and III are Standard Pressure for gases

I, III and V are Standard Pressure for gases

I, II and V are Standard Pressure for gases

IV and VI are Standard Pressure for gases

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Explanation

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5. What is standard temperature for gases?
I. 100 degrees Celsius
II. 0 degrees Celsius
III. 100 degrees Fahrenheit
IV. 0 Kelvin
V. 273.16 Kelvin

I (only) is correct

II (only) is correct

III (only) is correct

II and V are correct

II and IV are correct

The standard temperature for gases is 0 degrees Celsius (II) and 273.16 Kelvin (V). This is because 0 degrees Celsius is the freezing point of water and is commonly used as a reference point for temperature measurements. Kelvin is an absolute temperature scale where 0 Kelvin represents absolute zero, the lowest possible temperature where all molecular motion ceases. Therefore, II and V are correct.

Explanation

The standard temperature for gases is 0 degrees Celsius (II) and 273.16 Kelvin (V). This is because 0 degrees Celsius is the freezing point of water and is commonly used as a reference point for temperature measurements. Kelvin is an absolute temperature scale where 0 Kelvin represents absolute zero, the lowest possible temperature where all molecular motion ceases. Therefore, II and V are correct.

6. Where would air pressure be higher?

At the top of the Alps mountains

At sea level

Skiing in Colorado

More gas = more pressure. As you go higher in the atmosphere, there are less gas molecules.

Explanation

More gas = more pressure. As you go higher in the atmosphere, there are less gas molecules.

7. Which variable is most important to determine the average kinetic energy of gas particles?

Volume of the container

Volume of the particle

Mass of the container

Temperature

Kinetic energy: 1/2 mass x (velocity)^2

Explanation

Kinetic energy: 1/2 mass x (velocity)^2

8. Which would have more gas pressure?

1 moles of gas in a 22.4 L container (at STP).

2 moles of gas in a 22.4 L container (at STP).

2 moles of gas in a 11.2 L container (at STP).

More molecules in a smaller container will have the most collisions, therefore the most pressure.

Explanation

More molecules in a smaller container will have the most collisions, therefore the most pressure.

9. The number of atoms in one mole of gold is:

Avagodro's number

1.02 x 10^23

Dalton's number

Boyle's number

Avogadro's Law says that equal volumes of all gases contain the same number of molecules. The number of molecules in 1 mole of a gas is 6.02 x 10^23. This is called: Avogadro's number.

Explanation

Avogadro's Law says that equal volumes of all gases contain the same number of molecules. The number of molecules in 1 mole of a gas is 6.02 x 10^23. This is called: Avogadro's number.

10. Which of the following is NOT assumed by the kinetic-molecular theory?

Gas molecules are not significantly attracted to other gas molecules.

Collision between gas particles are elastic.

All gas molecules have the same mass.

All gas molecules move in a straight, constant motion.

The kinetic-molecular theory assumes that gas molecules are not significantly attracted to other gas molecules, that collisions between gas particles are elastic, and that all gas molecules move in a straight, constant motion. However, it does not assume that all gas molecules have the same mass. This is because different gas molecules have different masses, which can affect their behavior and properties.

Explanation

The kinetic-molecular theory assumes that gas molecules are not significantly attracted to other gas molecules, that collisions between gas particles are elastic, and that all gas molecules move in a straight, constant motion. However, it does not assume that all gas molecules have the same mass. This is because different gas molecules have different masses, which can affect their behavior and properties.