S1.5 - ideal gases Flashcards
What is an ideal gas?
Ideal gas - particles with a negligible volume and no attractive forces.
What are the 5 ideal gas assumptions?
1) Volume of a gas is negligible
2) There are no attractive forces between particles
3) There is a large number of identical molecules
4) Collisions are elastic and kinetic energy is conserved
5) Particles have a range of speeds and motions
What is a real gas?
Real gas - gas that has attractive forces and a volume; deviates from ideal gas laws
When does a real gas differ from and ideal gas?
- Low temperatures
- High pressures
What are limitations of the ideal gas model?
1) The volume of the gas particles is not negligible
2) There are attractive forces between particles
What is molar volume, and how do you calculate this?
Molar volume - volume occupied by 1 mole of a gas under standard conditions.
Molar volume = moles / volume
What is the ideal gas equation?
pV = nRT
What is the combined gas law equation?
P1C1 / V1 = P2C2 / V2
What is the pressure law?
Pressure is directly proportional to volume at a fixed temperature.
What is Boyle’s law?
Boyle’s law - pressure is inversely proportional to volume at a fixed temperature.
What is Charles’ Law?
Charles’ Law - volume is directly proportional to temperature at a fixed pressure.
What is the value for pv/rt for an ideal gas and what does a graph look like?
pV = nRT is equal to 1 (horizontal line)
What does a pv/nrt value smaller than 1 mean?
pV = nRT is smaller than 1 as there are attractive forces between particles which reduce the speed of collisions, making them less energetic and decreasing pressure
What does a pv/nrt value larger than 1 mean?
pV = nRT is larger than 1 as there is not a negligible volume and collisions between particles and walls of the container are more frequent than predicted
What are the conditions of STP?
273K and 100kPa
