Q: A barometer is used to measure atmospheric pressure. If the height of the mercury column is 76 cm, what is the pressure exerted by the column? (Given: $$\rho_{Hg} = 13.59 \times 10^3$ \ \mathrm{kg/m^3$}$$, $$g = 9.81 \ \mathrm{m/s^2$})$$

$$P = 1.01 \times 10^5$ \ \mathrm{Pa}$$

Question 1

Which of the following statements best explains why gases are highly compressible compared to liquids and solids?

Accepted Answer

The occupied volume of all gaseous molecules is negligible compared to the total volume, allowing them to be compressed easily.

Question 2

A barometer is used to measure atmospheric pressure. If the height of the mercury column is 76 cm, what is the pressure exerted by the column? (Given: $$ho_{Hg} = 13.59 	imes 10^3$ \ \mathrm{kg/m^3$}$$, $$g = 9.81 \ \mathrm{m/s^2$})$$

Accepted Answer

$$P = 1.01 	imes 10^5$ \ \mathrm{Pa}$$

Question 3

Which of the following is NOT a correct unit for measuring pressure?

Accepted Answer

Joule

Question 4

According to Boyle’s Law, what happens to the volume of a fixed amount of gas if the pressure is doubled at constant temperature?

Accepted Answer

The volume is halved.

Question 5

A balloon filled with air at room temperature is heated at constant pressure. According to Charles’s Law, what will happen to the volume of the balloon?

Accepted Answer

The volume will increase.

Question 6

Which equation correctly relates the pressure, volume, and temperature of an ideal gas?

Accepted Answer

$$PV = nRT$$

Question 7

At standard temperature and pressure (STP), what is the volume occupied by 1 mole of an ideal gas?

Accepted Answer

22.414 L

Question 8

Which statement about the kinetic-molecular theory of gases is correct?

Accepted Answer

The average kinetic energy of gas molecules is proportional to the absolute temperature.

Question 9

If the temperature of a gas is increased, what happens to the root-mean-square (rms) speed of its molecules?

Accepted Answer

It increases.

Question 10

Which of the following best describes Graham’s law of effusion?

Accepted Answer

The rate of effusion of a gas is inversely proportional to the square root of its molar mass.

Question 11

A sealed container contains a mixture of hydrogen and oxygen gases at the same temperature. Which statement is true regarding their average kinetic energies?

Accepted Answer

Both hydrogen and oxygen molecules have the same average kinetic energy.

Question 12

Which of the following is the correct expression for the density of a gas using the ideal gas law?

Accepted Answer

$$d = \dfrac{PM}{RT}$$

Question 13

A gas cylinder with a movable piston is injected with additional gas while keeping temperature and volume constant. What happens to the pressure inside the cylinder?

Accepted Answer

Pressure increases.

Question 14

Which of the following is a direct consequence of Avogadro’s Law?

Accepted Answer

Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

Question 15

If the atmospheric pressure at sea level is 1 atm, what would happen to the height of the mercury column in a barometer if the experiment is performed at a higher altitude?

Accepted Answer

The height of the mercury column would decrease.

Question 16

Which of the following best explains why a helium balloon floats in air?

Accepted Answer

Helium has a lower density than air.

Question 17

A sample of gas at 0°C and 1 atm occupies 22.4 L. If the temperature is increased to 273°C at constant pressure, what will be the new volume?

Accepted Answer

45.0 L

Question 18

Which of the following is the correct conversion between Celsius and Kelvin temperature scales?

Accepted Answer

$$T(K) = T(°C) + 273.15$$

Question 19

Which of the following is a key assumption of the kinetic-molecular theory of gases?

Accepted Answer

Gas molecules are in continuous and random motion.

Study Notes: Properties and Laws of Gases (General Chemistry, Chapter 10)

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