Chapter 10 - Properties of Gases

Flashcards for Chapter 10 - Properties of Gases

Kinetic Molecular Theory (KMT)

Assumes that gas molecules have negligible volumes compared to their container, don't interact with other gas molecules, move randomly and constantly, engage in elastic collisions, and have average kinetic energy proportional to temperature.

Properties of a Gas

Gases have neither definite shape nor volume, uniformly fill containers, change volume with temperature and pressure (expandable and compressible), exert pressure, mix completely, and are less dense than solids/liquids. Fully defined using P, V, T, and n.

Pressure (P)

Force exerted per unit area (SI unit is Pascal, Pa). Measured using a barometer for atmospheric pressure.

Boyle's Law

Volume of a gas varies inversely with applied pressure at constant temperature. V  1/P (T and n fixed)

Charles's Law

Volume of a gas at constant pressure is proportional to the temperature (K). V  T (P, n constant)

Absolute Zero

The temperature -273.15°C, where the volume of a gas is theoretically zero. Basis of the Kelvin scale.

Avogadro’s Law

Volume is directly proportional to the number of moles of gas at constant temperature and pressure. V  n (T, P constant)

Ideal Gas Law

PV = nRT, where P is pressure, V is volume, n is moles, R is the universal gas constant, and T is temperature.

Standard Temperature and Pressure (STP)

Reference condition for gases: 0°C and 1 atm. The molar volume of a gas at STP is 22.4 L/mole.

Combined Gas Law

Relates pressure, volume, and temperature of a gas when the number of moles is constant: (P1V1)/T1 = (P2V2)/T2

Dalton’s Law of Partial Pressures

The total pressure of a gas mixture is the sum of the partial pressures of each gas: PTotal = PA + PB + PC + …

Mole Fraction (X)

The ratio of the number of moles of a component in a mixture to the total number of moles in the mixture.

Diffusion

The process by which a gas spreads out through another gas to uniformly occupy the space.

Effusion

The process by which a gas flows through a small hole in a container.

Graham's Law of Effusion

The rate of effusion of a gas is inversely proportional to the square root of its molar mass: uA/uB = sqrt(MB/MA)

Real Gases

Deviate from ideal behavior at high pressure and low temperature due to volume and intermolecular forces.

van der Waals Equation

A modified version of the ideal gas law that accounts for the non-ideal behavior of real gases: (P + n²a/V²)(V - nb) = nRT