Lecture 32 11/21/05

2 seminars left

London Dispersion Forces:Induced dipole / Induced dipole

Non-polar / non-polar interaction

0.05 – 40 KJ/mol

Hydrogen Bonding

Kind of dipole-dipole interaction10 - 40 KJ/molMostly, X = F,N,O

p.490

Surface tension

Fig. 11-2, p.489

Fig. 11-3, p.490

Adhesive forces vs. Cohesive forces

Fig. 11-8, p.494

Changes of State

Energy (ice melting) = mass x heat of Fusion For water: 333 J/g or 6 KJ/mol

Energy (boiling) = mass x heat of Vaporization For water: 2256 J/g or 40.65 KJ/mol

You put 1 L of water in a pan at 100˚C and the water evaporates. How much heat was needed to vaporize all of the water?

ΔVvap˚ = + 40.7 KJ/mol at 100˚C

Density of water = 0.958 g/mL at 100˚C

(Equilibrium) Vapor Pressure

Liquid Vapor

Volatility: Greater the volatility the bigger the vapor

pressure

Fig. 11-4, p.491

If you put 2 L of water into a sealed room with a volume of 42500 L, will all of the water evaporate at 25˚C?

Assume density of water is 1 g/mL and vapor pressure is 0.0313 atm.

Boiling Point