ideal gases

regardless of composition, in particular conditions, gases are composed of molecules which all behave in the same way

phases of matter

liquid - fluid and can be condensed,
solid- can be condensed but not fluid
gas- cant be condensed but is fluid

condensed- refers to the where particles are fairly close to one another difficult to compress.

fluid- where intermolecular forces are weak and so the molecules are able to easily pass one another

solids- particle separation is similar to particle size but particles cannot translate
liquid- particles separation is similar to particle size and particles are able to translate
gas- particle separation is not similar to particle size but particles can translate around each other

all gases behave ideally if their density is low enough (as the IMF are generally weak and value is small compared to total volume)

based on 2 assumptions

no intermoelcular forces

particles have 0 volume

there is inverse proportionality between pressure and volume (Boyle's law)

there is a directly proportional relationship between volume and temperature (Charles Law)

directly proportional relationship between number of moles and volume (avogrados constant)

pv= nrt

pVm (molar volume)= RT

Daltons law

the pressure of the mixture of gases is equal to the sum of partial pressures of each gas

if 1 gas occupies a volume eg Va, with the set pressure (pa) and the second gas occumber a volume eg Vb with the set pressure (pb) separately we can form the following equations

paVa=naRT

when 2 gases mix we can find each gases new partial pressure using the following equation

p'a=pava//va+vb (total volume)

partial pressure

pressure a component gas would have occupied if it alone occupied the same volume

mixing 2 ideal gases
ptot=ntot x RT/V

  1. find the total number of moles of each gas by rearranging the equation for the number of moles and assigning a random temp
  2. add moles together and use to find final pressure

final pressure = initial pressure x (change in temp)/difference in volume

mole fractions = Pa = xa x ptot

xa= na/ntot

molecule inelastic collisions

kinetic energy is converted into rotational or vibrational energy via translation meaning that the total kinetic energy of all the molecules will change (unequal)- one particle will absorb energy into a different type so kinetic changes

elastic- conserved total kinetic energy of all particles colliding - can cause indicusal atoms to have different kinetic energies but the total will stray the same (conservation of energy theory)

both elastic and inelastic are equally probable so cancel each other out - but on average most collision are elastic

elastic collisions determine macroscopic properties and so atomic and molecular gases have to have the same properties in order to be ideal