Question 1

The pressure of a gas will increase when

Accepted Answer

According to Boyle's Law, the pressure of a gas is inversely proportional to its volume, meaning that as the volume of the gas decreases, the pressure it exerts will increase.

Question 2

A balloon is inflated outdoors on a cold day in North Dakota at a temperature of -35°C to a volume of 3.0 L.The pressure remains constant.What is the volume of the balloon indoors at a temperature of 25°C?

Accepted Answer

Using Charles's Law (V1/T1 = V2/T2), convert temperatures to Kelvin (238K and 298K), then solve for V2: V2 = (3.0 L * 298K) / 238K = 3.8 L, approximately 3.8 L, closest to 3.8 L.

Question 3

A gas is enclosed in a 15.0 L tank at 600 mm Hg pressure.Which of the following is a reasonable value for the pressure when the gas is pumped into a 3.00 L vessel?

Accepted Answer

According to Boyle's Law (P1V1 = P2V2), when the volume decreases, the pressure increases. The initial pressure is 600 mm Hg in a 15.0 L tank. When the gas is transferred to a 3.00 L vessel, the pressure increases to 3000 mm Hg (600 mm Hg * 15.0 L / 3.00 L = 3000 mm Hg).

Question 4

In a solution,the solvent is

Accepted Answer

The solvent is the substance present in larger amount in a solution, while the solute is the substance that is dissolved in the solvent. Therefore, option A is correct. Option B is incorrect because the solvent dissolves the solute, not the other way around. Option C is incorrect because the solvent can be any substance, not just water. Option D is incorrect because the solvent can be polar or nonpolar, depending on the solute and the type of solution.

Question 5

At a given temperature and pressure,the volume of a gas is directly proportional to the amount of gas present.This is a statement of

Accepted Answer

Avogadro's Law states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of the gas.

Question 6

The kinetic-molecular theory of gases assumes which of the following?

Accepted Answer

The kinetic-molecular theory of gases assumes that gas molecules move constantly and in straight lines. This theory also assumes that gas molecules do not have significant interactions with each other, and that the total amount of energy in a system remains constant. Additionally, the theory assumes that the average kinetic energy of gas molecules is directly proportional to the temperature of the gas. Therefore, options A, B, and C are not in line with the kinetic-molecular theory of gases.

Question 7

The density of O₂ gas at STP is

Accepted Answer

At standard temperature and pressure (STP), the density of any gas is 1.43 g/L. This is because STP is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atmosphere (1 atm), and the molar volume of any gas at STP is 22.4 L/mol. Therefore, to find the density of a gas at STP, we simply divide the molar mass of the gas by the molar volume at STP: (32 g/mol) / (22.4 L/mol) = 1.43 g/L. Since the molar mass of O₂ is 32 g/mol, the density of O₂ gas at STP is 1.43 g/L.

Question 8

According to the kinetic-molecular theory,gas molecules have

Accepted Answer

The kinetic-molecular theory suggests that gas molecules have weak interactions between each other. This allows them to move rapidly and randomly in all directions, assuming the shape and volume of the container they are in.

Therefore, option B is the correct answer. Options A, C, and D are incorrect as gas molecules have weak interactions and a lot of space between them. They have high kinetic energy compared to solid molecules.

Question 9

A gas is enclosed in a cylinder fitted with a piston.The volume of the gas is 5.00 L at 0.500 atm pressure.The piston is moved to increase the volume to 3.00 L.Which of the following is a reasonable value for the pressure of the gas at the greater volume?

Accepted Answer

According to Boyle's law, at constant temperature, the product of pressure and volume is a constant. This means that if the volume is decreased, the pressure will increase, and vice versa. Using the initial and final volumes and pressures, we can set up the following equation:
P1V1 = P2V2
(0.500 atm)(5.00 L) = P2(3.00 L)
Solving for P2, we get:
P2 = (0.500 atm)(5.00 L) / 3.00 L
P2 = 0.833 atm
Therefore, a reasonable value for the pressure of the gas at the greater volume is B) 0.833 atm.

Question 10

At STP,22.4 liters of nitrogen gas,N₂,will have a mass of

Accepted Answer

At STP, the molar volume of a gas is 22.4 L/mol. The molar mass of nitrogen gas, N₂, is 28.0 g/mol. Therefore, 22.4 L of N₂ will have a mass of 28.0 g. So, the correct answer is (C) 28.0 g.

Question 11

At STP,1 mole of oxygen gas,O₂,will have a mass of

Accepted Answer

At STP, 1 mole of oxygen gas (O₂) has a molar mass of 32.0 g/mol, as each oxygen atom has a mass of 16.0 g/mol and there are two atoms in an O₂ molecule.

Question 12

A gas is enclosed in a 10.0 L tank at 1200 mm Hg pressure.Which of the following is a reasonable value for the pressure when the gas is pumped into a 5.00 L vessel?

Accepted Answer

Boyle's law: P1V1 = P2V2P2 = P1V1/V2 = (1200 mm Hg)(10.0 L)/(5.00 L) = 2400 mm Hg

Question 13

For a given amount of gas at a constant temperature,the volume of gas varies inversely with its pressure is a statement of ________ Law.

Accepted Answer

This is Boyle's Law, which states that at a constant temperature, the pressure and volume of a gas are inversely proportional to each other. As one goes up, the other goes down, and vice versa. This law is commonly expressed as PV = k, where P is pressure, V is volume, and k is a constant.

Question 14

Which of the following is NOT a postulate of the kinetic-molecular theory?

Accepted Answer

The postulate that molecules of a gas are strongly attracted to each other is not a part of the kinetic-molecular theory. In fact, the theory assumes that there are no attractive or repulsive forces between gas molecules, and they move independently of each other. The other three options, (A) Molecules of a gas move rapidly and in straight lines, (B) The molecules in a gas are tiny compared to the distance between them, and (D) If two molecules collide with each other, the total energy of the molecules before the collision is the same as their total energy after the collision, are all key postulates of the kinetic-molecular theory.

Question 15

At STP,22.4 liters of krypton gas,Kr,will have a mass of

Accepted Answer

At STP, one mole of any gas occupies 22.4 liters. The molar mass of krypton (Kr) is approximately 83.8 g/mol, so 22.4 liters of krypton gas will have a mass of 83.8 g.

Question 16

The volume of one mole of krypton at STP is

Accepted Answer

According to the Avogadro's law, one mole of any gas at standard temperature and pressure (STP) occupies 22.4 liters of volume. Therefore, the volume of one mole of krypton at STP is 22.4 liters.

Question 17

Charles's Law relates the volume and temperature of a gas sample at constant pressure.What would be the temperature of a gas sample when its volume is 0 L?

Accepted Answer

According to Charles's Law, the volume of a gas sample is directly proportional to its temperature if the pressure and amount of gas are constant. As the volume approaches 0, the temperature must also approach absolute zero, which is -273°C or 0 K. Therefore, the temperature of a gas sample with a volume of 0 L would be -273°C or 0 K. Since -273°C is a lower temperature than 0°C, the answer cannot be C, and since the temperature must be measured in absolute units, the answer cannot be A or D.

Question 18

The statement that the volume of a fixed amount of a gas at a constant pressure is directly proportional to its absolute temperature is known as ________ Law.

Accepted Answer

This law, also known as the law of volumes, states that at a constant pressure, the volume of a given mass of gas is directly proportional to its absolute temperature, i.e., V ∝ T. This law is named after the French physicist Jacques Charles who first observed it in the late 18th century. Boyle's Law relates the pressure and volume of a gas, Gay-Lussac's Law relates the pressure and temperature of a gas, and Avogadro's Law relates the volume and number of moles of a gas.

Question 19

A sample of gas at a temperature of 350 K has a volume of 4.00 L.The pressure remains constant.What is the volume of the gas at a temperature of 175 K?

Accepted Answer

According to Charles's Law, which states that volume is directly proportional to temperature at constant pressure, the volume of the gas will decrease as the temperature decreases. Since the temperature is halved from 350 K to 175 K, the volume will also halve from 4.00 L to 2.00 L.

Question 20

The density of Xe at STP is

Accepted Answer

The density of Xe at STP is 5.86 g/L.

Quiz 6: Gases, Liquids, Solids, and Intermolecular Forces