Ideal gases

Pressure

The force per unit area from molecules colliding with container walls.

Kinetic-Molecular Theory of Gases

Relates gas behavior to molecular properties like velocity and collision frequency.

Boyle's Law

Pressure is inversely proportional to volume at constant temperature (PV = constant).

Charles' Law

Volume is directly proportional to temperature at constant pressure (V/T = constant).

Avogadro's Principle

Volume per mole of gas at fixed temperature and pressure is the same for all gases (V/n = constant).

Ideal Gas Equation

PV = nRT, relating pressure, volume, temperature, and number of moles.

Dalton's Law of Partial Pressures

Total pressure equals the sum of the partial pressures of gases in a mixture (P = PA + PB + PC).

Intermolecular Forces

Attractive forces between molecules affecting gas properties.

Real Gases

Gases that show deviations from ideal behavior under certain conditions.

Van der Waals Equation

Equations correcting for volume and pressure in real gases.

Molar Volume at STP

22.4 dm³ per mole, the volume occupied by one mole of gas at standard temperature and pressure.

Gas

A state of matter with particles spaced widely apart, no fixed shape or surface.

Liquid

A state of matter with particles closely spaced but unordered, able to diffuse.

Solid

A state of matter with particles tightly packed and strong attractions, fixed volume.

London Forces

Weak attractive forces present in all molecules, increasing with the size of the molecule.

Dipole Moment

An interaction in polar molecules, which depends on electronegativity differences.

Induction Forces

Forces arising from temporary dipoles due to proximity of polar and non-polar molecules.

Kinetic Energy (KE) for gases

Simplifies to KE = 3/2 kT for gases.

Root Mean Square Velocity (vrms)

vrms = √(3RT/M), measures average molecular speed.

Mean Velocity (v̅)

v̅ = √(8RT/πM), average speed of gas molecules.

Mode Velocity (v*)

v* = √(2RT/M), most probable speed of gas molecules.

Pressure Correction in Van der Waals

Preal = Pideal - a(n/V)², accounts for intermolecular attractions.

Volume Correction in Van der Waals

Vreal = Videal + nb, accounts for the volume occupied by gas molecules.

Combined Gas Law

P1V1/T1 = P2V2/T2, relating variables for a fixed mass of gas.

Gas Laws

Mathematical relationships describing the behavior of gases.

Mole Fraction (xA)

Calculated as xA = nA/(nA + nB + nC), representing gas amount in mixtures.

Ideal Gases

Hypothetical gases that follow the ideal gas laws perfectly without interactions.

Pressure Units

1 atmosphere = 101325 Pascal = 1.01325 bar = 760 Torr.

Fixed Volume

Characteristic of solids and liquids, where volume does not change.

Diffusion

The movement of particles from areas of higher concentration to lower concentration.

Gas Properties

Determined by the interactions of gas molecules and external conditions.

Collision Frequency

The rate at which gas molecules collide with the walls of their container.

Molecular Velocity

The speed at which gas molecules move, affecting pressure.

Temperature in Kelvin

Temperature must be measured in Kelvin for gas law calculations.

Pressure-Volume Isotherms

Graphs showing the relationship between pressure and volume at constant temperature.

Equilibrium

A state where the properties of a system remain constant despite ongoing processes.

Mixture

A combination of two or more substances where each retains its individual properties.

High Pressure Conditions

Conditions under which real gases deviate from ideal gas behavior.

Low Volume Conditions

Conditions that can cause real gases to deviate from ideal behavior.

Hydrogen Bonds

Strong attractions between molecules, significantly affecting water's properties.

Kinetic Energy Equation

KE = 1/2 mv², representing the energy of a moving object.

Temperature and Pressure Relation

Increasing temperature raises pressure in a gas at constant volume.

Consistent Units

Using the same system of measurement for calculations.

Volume Expansion

The increase in volume a substance experiences upon heating.

Gas Behavior

The predictable patterns observed in gases, explained by laws of thermodynamics.

Insights from Gases

Understanding gas properties helps to model more complex systems.