Notes on Solutions

Qualitative ways of describing solutions

• Dilute vs. concentrated

• Unsaturated, saturated, supersaturated

• Miscible/immiscible

• Solute, solvent, solution

Quantitative methods(memorize formulas)

• Molarity

M = mol solute

1 liter sol’nn

• % Mass

• Dilution (M1V1 = M2V2)

Factors affecting RATE of solution

(how fast it dissolves)

• Temperature

• Agitation (stirring)

• Surface area

• Video

Solubility of solids(how well it dissolves)

• Nature of solute and solvent

• “Like dissolves like”

• As temperature increases, most solids become MORE soluble

• Pressure does NOT affect solubility of solids

Solubility of gases

• As temperature increases, solubility of gases DECREASES because of kinetic energy

• As pressure increases, solubility of gases INCREASES

Be able to read solubility curves

Know the steps for making a standard solution.

Know the steps for diluting a solution (M1V1 = M2V2 )

Properties of Solutions - Electrolytes

• Strong electrolytes (use solubility rules)

• Weak electrolytes (weak acids and bases)

• Non-electrolytes (dissolve but DO NOT break apart into ions; e.g. sugar)

Colligative Properties of Solutions

1. Vapor pressure lowering2. Boiling point elevation3. Freezing point depressionThese properties depend

ONLY on the number of particles in

solution.

Earth is at the triple point!

Calculations of Boiling Point Elevation and Freezing Point

Depression

Tb = Kb x m x i

Tf = Kf x m x i

• Kf and Kb are constants (given to you)

• Van’t Hoff factor (i) is the number of ions that a solute dissolves into– How many particles a substance will dissolve into:

» NaCl Na+ + Cl-

Bonding in H2O

• Polar covalent bonds between H and O within the molecule

• Bent shape• Polar molecule

overall• Hydrogen bonding

between multiple water molecules

Hydrogen Bonding

Hydrogen Bonding

Properties of H2O

• Good solvent• High surface tension• Adhesion/Cohesion• Low vapor pressure

• High heat of vaporization

• High boiling point• High specific heat

capacity• Solid (ice) is less

dense than liquid• Blue in color (appears

clear in small quantities)