Ideal Gas Law PV = nRT PV (L atm) P (atm) ideal gas SO no volume no interactions van der Waals P + n 2 a V2V2 ( V – nb) = nRT a = interactive force b = molecular diameter gasliquidsolid

Ideal gas kinetic energymotion increase T K.E. = increase energy ½ mv 2 K.E. ave =3/2 RT heat capacity energy K CvCv = 3/2 R

Non-Ideal gas kinetic energymotion K.E. = ½ mv 2 = K.E. translation + K.E. vibration + K.E. rotation He H2H2 degrees of freedom= 3n 3 translation H2OH2O Rn

Non-Ideal gas molar heat capacity ideal gas3/2 R heat required to change the temperature of 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  degrees of freedom energy strength of Intermolecular Forces

Non-Ideal gas kinetic energymotion K.E. = ½ mv 2 = K.E. translation + K.E. vibration + K.E. rotation electrostatic P.E. = Coulomb’s Law Q1Q2Q1Q2 4   0 r charge distance potential energy position P.E. r 0 related to a P.E. bond P.E. IMF ++

He -- ++ small short lived strength increases size He Ne Ar Kr Xe Rn e-e- b.p e-e- e-e e-e- 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 pentane neo-pentane C 5 H 12 b.p. = 36 o C b.p. = - 9 o C size van der Waals forces =  all types of forces London Forces (2 kJ/mol)all types of molecules Intermolecular Forces

van der Waals forces =  all types of forces dipole - dipolepolar molecules permanent charge separation HCl London Forces (2 kJ/mol)all types of molecules dipole (2 kJ/mol) -- ++ -- -- ++ ++ ++ ++ -- -- -- -- ++ C 2 H 2 Cl 2 CO 2

Intermolecular Forces van der Waals forces =  all types of forces dipole - dipolepolar molecules London Forces (2 kJ/mol)all types of molecules (2 kJ/mol) hydrogen bonding (20 kJ/mol) donors and acceptors N-H O-H F-H ++ ++ ++ F-F- -O--O- -N--N- -- -- -- -- ++ ++ ice less dense than water high heat capacity

Intermolecular (Interionic) Forces Ion-dipole ions and polar molecules NaCl + H 2 O Na + Ion-ion metals and non-metals NaCl 250 kJ/mol large charges small distances m.p.800 o C (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 wax imbalance in IMFminimize surface surface tension  IMF glass is Si and O H-bond to water capillary action cohesionadhesion

Viscosity fluid’s resistance to flow  IMF CCl 4 water glycerol 9.7 x Ns/m x decreases with temperature