Physical Chem Topic 2

Ideal Gas

A hypothetical gas composed of many particles that are in continuous random motion and that, when colliding, do not lose energy.

Boyle’s Law

At constant temperature, the pressure of a fixed amount of gas is inversely proportional to its volume.

Charles’ Law

At constant pressure, the volume of a fixed amount of gas is directly proportional to its absolute temperature.

Avogadro’s Principle

For a fixed temperature and pressure, equal volumes of gases contain the same number of moles.

Van der Waals Forces

Attractive forces between molecules that correct for non-ideal gas behavior.

Pressure (P)

The force exerted by gas molecules colliding with the walls of its container.

Volume (V)

The amount of space that a gas occupies.

Temperature (T)

A measure of the average kinetic energy of the particles in a substance.

Pressure Units

Different measurements of pressure including Pascal, atm, bar, and Torr.

Mean Free Path (λ)

The average distance a molecule travels between collisions.

Kinetic Energy (KE)

The energy that a molecule has due to its motion.

Collision Frequency (zf)

The number of collisions of one molecule per second.

Collision Rate (zrate)

The total number of collisions of all molecules in a volume of 1 m³ per second.

Real Gas vs. Ideal Gas

Real gases deviate from ideal gas behavior under high pressure and low temperature.

Critical Temperature (Tc)

The temperature above which a gas cannot exist as a liquid.

Molecular Velocity

The speed of gas molecules, which can vary in a distribution.

Intermolecular Forces

Forces of attraction or repulsion between neighboring particles.

Hydrogen Bonding

A strong type of dipole-dipole interaction that occurs between molecules containing H bonded to highly electronegative atoms.

Dalton’s Law

In a mixture of gases, the total pressure is equal to the sum of the partial pressures of each individual gas.

Elastic Collisions

Collisions in which there is no net loss of total kinetic energy, common in ideal gases.

Ideal Gas Equation

The equation PV = nRT that relates pressure, volume, and temperature in ideal gases.

Standard Temperature and Pressure (STP)

Conditions defined as 0 °C (273.15 K) and 1 atm used for measurements.

Kelvin (K)

The SI unit of temperature, measured from absolute zero.

Mole Fraction (x)

The ratio of the amount of a component to the total amount of all components in a mixture.