The Gas State
Gay Lussac’s Law
Pressure Temperature Law
Dalton’s Laws or Partial Pressures
The kinetic-molecular theory of gases can be stated as four postulates:
A gas consists of molecules in constant random motion.
Gas molecules influence each other only by collision; they exert no other forces on each other.
All collisions between gas molecules are perfectly elastic; all kinetic energy is conserved.
The volume actually occupied by the molecules of a gas is negligibly small; the vast majority of the volume of the gas is empty space through which the gas molecules are moving.
STP Standard temperature and pressure
Temperature = 0o C or 273.14 K
Pressure = 101.325 kPa
Volume = 22.4 L
SATP Standard ambient temperature and pressure
Temperature = 25oC or 298 K
Pressure = 100 kPa
Volume = 24.8 L
Universal Gas Constant R = 8.314 J/mol K or 8.314 kPa dm3/mol K
Commonly used units of pressure
Kilopascal kPa Conversion unit 1atm/101.325 kPa
Toricelli torr. Conversion unit 1atm / 760 torr
Millimeter mm Conversion unit 1 atm / 760 mm
1 atm. = 101.325 kPa = 760 torr = 760 mm
Celsius and Kelvin
Conversion: Kelvin = degrees Celsius + 273
K = oC + 273
In all SI metric calculations use only Kelvin values.