Mullis 1

Strong Electrolytes ( 100% ionized) A. Strong Acids: HCl, HBr, HI, H2SO4, HNO3, HClO4, HClO3 B. Strong Bases: Hydroxides of group IA and II A, Except Be and Mg C. Soluble Salts ( ionic compounds: metal/nonmetal) Always Soluble if these are in a compound Except with NO3

-, Group IA, NH4+, CH3COO-, ClO4

-, ClO3- No Exceptions

Cl- Br-, I- Pb, Ag, Hg2

2+ SO4

2- Ag, Pb, Hg22+

Ca, Sr, Ba

Mullis 2

Concentration Measurements

Molarity = M = moles of solute

volume of solution in L

molality = m = moles of solute mass of solvent in kg

Mole = X = moles of substance S Fraction total moles in solution

Mullis 3

Colligative properties

van’t Hoff factor = ii = number of ions one unit of substance

will dissociate into in solution CaCl2 dissociates into Ca2+, Cl- and Cl-, so i= 3.

Boiling Point Elevation

ΔT = ikbm

ΔT = increase in solution boiling point

kb = boiling point elevation constant for the solvent

m = molality

(for now)

Mullis 4

Freezing Point DepressionΔT = ikfm

ΔT = decrease in solution freezing pointkf = freezing point depression constant for the solvent

m = molality

Vapor Pressure LoweringP = XPº

P = vapor pressure of the solutionX = mole fraction of the solventPº = vapor pressure of the pure solvent

Add solute: Solution’s vapor pressure goes down.Lower vapor pressure = Raise boiling point

Mullis 5

Solubility ProductFor the reaction:

AaBb(s) a Ab+(aq) + b Ba-(aq)

The solubility expression is:

Ksp = [Ab+]a[Ba-]b

Example: The solubility of strontium fluoride in water is 1 x 10-3 M at room temp. What is the value of its solubility product?

[Sr2+] = 1 x 10-3 M and [F-] = 2 x 10-3 M

SrF2 Sr2+ + 2F- so Ksp = [Sr2+][F-]2

Ksp = [1 x 10-3 M][2 x 10-3 M]2 = 4 x 10-9

Mullis 6

Intermolecular forces: Generalizing properties

Low boiling point = particles are more likely to leave liquid solution

Weaker IM forces = lower boiling point Lower boiling point = more vapor = higher vapor

pressure High boiling point = slow evaporation If IM forces are the same, look at formula weight.

Heavier molecules have higher boiling points. Strength of IM forces: Hydrogen bond>dipole-dipole>London dispersion

Mullis 7

Intermolecular Forces (Chart from Chemistry: The Central Science by Brown-LeMay et al.)

Interacting molecules or ions

Polar molecules? Ions involved? Are polar molecules and ions both present?

Are H atoms bonded toN,O or F atoms?

No Yes

Yes

London ForcesonlyEx. Ar(l), I2(s)

No

Dipole-Dipole

Ex. H2S

No

Hydrogen BondingEx. NH3, H2O

Yes

Ion-dipole ForcesEx. KBr in H2O

Yes

Ionic bondingEx. NaCl

No