1. Kinetic-Molecular Theory (KMT)
motion of particles (energy, collisions)
1) constant particle motion
2) Pressure caused by collisions
3) IMAFs are negligible
4) Volume of particles is negligible
compared to total volume
(Vgas = Vcontainer – Vparticles)
5) Average KE directly proportional to Kelvin Temp (T , KE)

2. PV = nRT P ↑ , V ↓ T ↑ , V ↑ P1V1 n1T1 P2V2 n2T2 = T ↑ , P ↑ n ↑ , V ↑
R = L∙atm/mol∙K
inverse
T ↑ , V ↑
P1V1
n1T1
P2V2
n2T2 =
T ↑ , P ↑
(changes in P,V,T,n)
n ↑ , V ↑
direct
Ptotal = PA + PB + PC + …
PA = Ptotal x XA
XA: mol fraction
moles of A
Molar Volume: 22.4 L/mol
XA =
@STP
total moles

3. Temp, KE, & Molecular Speed
KE = ½ mv2
↑T a ↑KE
KMT states:
KE = ½ mv2
½ mv2 = ½ mv2
At same T :
(same KE)
↑M , ↓v

4. Ideal Gas vs Non-Ideal Gas
T: ↑
P: ↓
NON
T: ↓
P: ↑
more KE
weaker IMAFs
more Vtotal
less KE
stronger IMAFs
less Vtotal
IMAFs
(ideal P)
(ideal V)
n2a V2
) (V ) = nRT (P +
− nb
“observed” V too high b/c
size of particles
not negligible
compared to total volume
“observed” P too low b/c attractive forces not negligible,
collisions less frequent and of less force
Vgas = Vcontainer
– Vparticles