Chemistry - Gases

Boyle’s Law

for a fixed mass of gas at constant temperature, pressure is inversely proportional to volume

Charles’ Law

for a fixed mass of gas at constant pressure, volume is directly proportional to temperature

24 litres

one mole of any gas occupies this volume at RTP (room temperature and pressure)

Gay Lussac’s Law

in a reaction between gases, the volumes of the reacting gases and the values of any gaseous products are in the ratio of small whole numbers provided the volumes are measured at the same temperature and pressure

Avogadro’s Law

equal volumes of gases contain equal numbers of molecules under the same conditions of temperature and pressure

22.4 litres

one mole of any gas occupies this volume at STP (standard temperature and pressure)

Kinetic Theory of Gases

• gases consist of small particles in continuous motion that collide

• there are no attractive or repulsive forces between the molecules of a gas

• gas molecules are so small and widely separated that the actual volume of the molecules is negligible compared to the space they occupy

• collisions between molecules of a gas are perfectly elastic

• average kinetic energy of the molecules in a gas is proportional to the temperature measured in Kelvin

Low Pressure and High Temperature

gases come closest to ideal behaviour at…

Ideal Gas

obeys all the assumptions of the kinetic theory at all temperatures and pressures

Smaller Molecules

are closer to ideal than larger molecules as they have less Van der Waal’s Forces

Non Polar Molecules

are closer to ideal behaviour than polar molecules

Pascals

unit of pressure in the ideal gas equation

Kelvin

unit of temperature in the ideal gas equation

M³

unit of volume in the ideal gas equation

10^-6

multiply by this to change from cm³ to m³

Volatile Liquid

has a low boiling point