L1 /
2
CH1012
REAL GASES
REAL GASES
(i) at low p & high T » ideal gas (eg. 1atm, 25oC)
(i) at low p & high T » ideal gas (eg. 1atm, 25oC)
(ii) high p
& / or low T 2 types of deviations:
1) Total volume of particles is not
negligible
container
volume V
> than the free volume
available to the gas molecules
available to the gas molecules
pV/RT
> 1 at high p (1 mol of gas)
N2 p = 500atm, 300K pV/RT = 1.4 Videal0.05 Vmeas 0.07dm3
N2 p = 500atm, 300K pV/RT = 1.4 Videal0.05 Vmeas 0.07dm3
2) Intermolecular
attractive forces are not negligible - lowers pressure p
pV/RT < 1 at low T (1 mol of gas)
N2 V = 1m3, 100K pV/RT = 0.7 pideal831 pmeas 582Pa
N2 V = 1m3, 100K pV/RT = 0.7 pideal831 pmeas 582Pa
