Ideal Gas Law PV = nRT

PV(L atm)

P (atm)

24.88 ideal gas

SO2

1.0 3.0 5.04.52

21.43

no volumeno interactions

van der Waals

P + n2 aV2

( V – nb) = nRT

a = interactive force

b = molecular diameter

gas liquid solid

Ideal gas

kinetic energy motion

increase T

K.E. =

increase energy

½ mv2

K.E.ave = 3/2 RT

heat capacity

energyK

Cv = 3/2 R

Non-Ideal gas

kinetic energy motion

K.E. = ½ mv2 = K.E.translation + K.E.vibration+ K.E.rotation

He

H2

degrees of freedom = 3n 3 translation

H2O

Rn

Non-Ideal gas

molar heat capacity

ideal gas 3/2 R

heat required to change the temperatureof 1 mole, 1K

K.E.translation

non-ideal gas K.E.translation + K.E.rotation + K.E.vibration

energy = heat capacity x T T =

heat capacity

heat capacity degrees of freedom

energy

strength of Intermolecular Forces

Non-Ideal gas

kinetic energy motion

K.E. = ½ mv2 = K.E.translation + K.E.vibration+ K.E.rotation

electrostatic

P.E. = Coulomb’s Law Q1Q2

4 0 rchargedistance

potential energy position

P.E.

r

0

related to a

P.E.bond

P.E.IMF

++

He

- +

small short lived

strength increases

size

HeNeArKrXeRn

21018365486

-269-246-186-152-107-62

e- b.p.

2+

e-

e-

2+

e-

e-

shape

van der Waals forces

London Forces

= all types of forces

(2 kJ/mol) all types of molecules

dipole - +

short distance

polarizibility

instantaneous

Intermolecular Forces

shape

pentaneneo-pentane

C5H12

b.p. = 36oC b.p. = - 9oC

size

van der Waals forces = all types of forces

London Forces (2 kJ/mol) all types of molecules

Intermolecular Forces

Intermolecular Forcesvan der Waals forces = all types of forces

dipole - dipole polar molecules

permanent charge separationHCl

London Forces (2 kJ/mol) all types of molecules

dipole

(2 kJ/mol)

-+

- -

+ ++ +

-

-

- -+

C2H2Cl2

CO2

Intermolecular Forcesvan der Waals forces = all types of forces

dipole - dipole polar molecules

London Forces (2 kJ/mol) all types of molecules

(2 kJ/mol)

hydrogen bonding (20 kJ/mol) donors and acceptorsN-HO-HF-H

+

+

+ F--O--N--

-

--

+

+

ice less dense than water

high heat capacity

Intermolecular (Interionic) Forces

Ion-dipole ions and polar molecules

NaCl + H2O

Na+

Ion-ion metals and non-metalsNaCl

250 kJ/mol large charges small distancesm.p. 800oC

(aq) + Cl- (aq)

Intermolecular Forces

HCl HBr

b.p. = 189 K b.p. = 206 K

18 e- 36 e-more polar stronger LDF

Solubility“likes dissolve likes” compatible IMF

Surface Tension

water on waximbalance in IMF minimize surfacesurface tension IMF

glass is Si and O

H-bond to water capillary action

cohesion adhesion

Viscosity

fluid’s resistance to flow IMF

CCl4

water

glycerol

9.7 x 10-4

Ns/m2

1.0 x 10-3

1.49

decreases with temperature