Kinetic Theory and Pressure of Gases

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Questions and Answers

What is the definition of mole fraction in a gas mixture?

The ratio of moles of a specific gas to the total moles of all gases present (correct)

A measurement of the volume occupied by a gas

The total number of gas particles in a mixture

The pressure exerted by a specific gas in a container

How is the partial pressure of a gas in a mixture calculated?

By measuring the volume of the gas in the container

By subtracting the total pressure from the pressure of the gas

By using the ideal gas law only

By multiplying the mole fraction of the gas by the total pressure (correct)

If the total pressure of a gas mixture is 1.37 atm, what is the partial pressure of propane (C3H8) given its mole fraction of 0.0132?

0.0132 atm

0.0181 atm (correct)

0.0240 atm

0.0086 atm

What happens to the pressure in a container when 4 moles of gas are added to 1 mole already present?

The pressure will be five times higher. Signup and view all the answers

At the same temperature and pressure, a 3.1-L sample of hydrogen compared to 0.20 mol of carbon dioxide contains:

The same number of molecules Signup and view all the answers

Which of the following characteristics applies to gases?

Gases assume the volume and shape of their containers. Signup and view all the answers

How is pressure defined in the context of gases?

The forces exerted by gas on the walls of the container. Signup and view all the answers

What unit is used to measure atmospheric pressure?

Pascal Signup and view all the answers

According to Boyle's Law, how is the volume of a gas related to pressure at constant temperature?

Volume is inversely proportional to pressure. Signup and view all the answers

What happens to the volume of a gas when temperature increases at constant pressure?

Volume increases. Signup and view all the answers

Which of the following calculations involves finding the new volume of a weather balloon as it rises?

V2 = V1 * P1/P2. Signup and view all the answers

What is the temperature in Kelvin for a gas at 150°C?

423.2 K Signup and view all the answers

Which of the following statements about vapor is accurate?

Vapor is the gaseous form of any substance that is liquid or solid at normal temperatures or pressure. Signup and view all the answers

What is the relationship between the volume of a gas and the number of moles of gas at constant temperature and pressure?

Volume is directly proportional to the number of moles. Signup and view all the answers

What is the temperature of the air inside the tire measured when the tire pressure is 176 kPa?

Unknown without more data. Signup and view all the answers

What is the PV=nRT equation used to calculate?

The volume of gas calculated from moles, pressure, and temperature. Signup and view all the answers

What is stated by Amonton's Law?

At constant volume, pressure of a gas is directly proportional to its absolute temperature. Signup and view all the answers

How is the total pressure of a mixture of gases determined?

Total pressure is the sum of the individual gas partial pressures. Signup and view all the answers

What will happen to the volume of a gas if the pressure doubles while temperature remains constant?

The volume will be halved. Signup and view all the answers

What is the molar mass of a gas calculated using the formula M = dRT/P?

It is determined by the density, ideal gas constant, and pressure. Signup and view all the answers

What will be the volume occupied by 2 moles of a gas at 273.15 K and 1 atm pressure?

44.86 L. Signup and view all the answers

Study Notes

Kinetic Theory of Gases

Gases are characterized by widely separated molecules in rapid motion.
Gases occupy the volume and shape of their containers.
Gases are highly compressible.
Gases mix evenly and completely when confined to the same container.
Gases have much lower densities than liquids and solids.
Gases are normally in the gaseous state at 25°C and 1 atm pressure.
Vapor is the gaseous form of a substance that is liquid or solid at normal temperatures or pressures.

Definition of Pressure

Pressure is the force exerted by gas on the walls of the container.
Pressure = Force/Area
SI unit of pressure is the Pascal (Pa) = N/m² = (kg m s⁻²)/m² = 1 kg/ms².
Gas pressure is measured relative to atmospheric pressure.
Atmospheric pressure changes with distance from Earth's surface.
Gas pressure is measured using a barometer invented by Torricelli.
Unit of barometer measurement is 1 Torr = 1 mm Hg.
1 atm pressure = 760 mm Hg = 760 Torr.
1 atm is equivalent to 101325 Pa = 101.325 kPa.

Boyle's Law

The volume of a gas is inversely proportional to its pressure at constant temperature and number of moles.
P α 1/V
P * V = constant
P₁ * V₁ = P₂ * V₂

Charles' and Gay-Lussac's Law

At constant pressure, the volume of a fixed quantity of gas is directly proportional to its absolute temperature.
V α T
V/T = constant
V₁/T₁ = V₂/T₂
Temperature must be in Kelvin (K).
T(K) = t(°C) + 273.15

Amonton's Law

The pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.
P α T
P/T = constant
P₁/T₁ = P₂/T₂

Avogadro's Law

The volume of a gas at constant temperature and pressure is directly proportional to the number of moles of gas.
V α n
V/n = constant
V₁/n₁ = V₂/n₂

Ideal Gas Equations

The ideal gas law combines Boyle's, Charles', Gay-Lussac's, and Avogadro's laws.
PV = nRT
R is the gas constant = 0.082057 L atm/mol K.

Dalton's Law of Partial Pressures

The total pressure of a mixture of gases is the sum of the partial pressures of the individual gases.
P₁otal = P₁ + P₂ + ...
V and T are constant.
Partial pressure of gas i (Pᵢ) = Xᵢ * Pₜₒₜₐₗ
Xᵢ is the mole fraction of gas i, which is the ratio of the moles of gas i to the total moles of gases in the mixture.

Gas Density Calculations

Gas density (d) is mass (m) per unit volume (V).
d = m/V
PV = nRT can be rewritten as PV = mRT/M
d = PM / RT
M is the molar mass of the gas.

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Description

Explore the fundamental concepts of the Kinetic Theory of Gases and the definition of pressure. This quiz covers the characteristics of gases, how pressure is defined and measured, and the relationship between gas pressure and atmospheric pressure. Test your knowledge on these essential topics in chemistry.