Lectures 5-7

Question 1

Molarity

Answer 1

Moles of solute / Liters of solution

Question 2

Molality

Answer 2

Moles of solute / Kilograms of solvent

Question 3

Weight Percent

Answer 3

Mass of solute / Mass of solution * 100

Question 4

Weight by Mass Percent

Answer 4

Mass of solute / Volume of solution; must be in g/L or kg/L

Question 5

Mole Fraction

Answer 5

Moles of solute / Moles of total solution

Question 6

Colligative Properties

Answer 6

Physical properties of solutions dictated by the number of solute particles (NOT the chemical itself)

Question 6

Osmosis

Answer 6

Osmosis: Flow of solvent into the solution through a semipermeable membrane; higher solute concentration to lower solute concentration

Question 7

Colloid

Answer 7

A suspension of tiny particle in some medium (not dissolving)

Question 8

Coagulation

Answer 8

Destruction of a colloid; usually accompanied by heating or adding an electrolyte

Question 9

Aerogel

Answer 9

Lowest density solids known; good thermal, electric, and sound insulator and strong

Question 10

Tyndall Effect

Answer 10

Scattering of light by particles

Question 10

Boiling Point Elevation / Freezing Point Depression

Answer 10

∆T = k(b or f) * m * i
∆T = change in temperature
k (b or f) = boiling or freezing point constant
m = molality
i = Van’t Hoff Factor (ratio between number of particles of solute and number of particles of solvent)

Question 11

Raoult’s Law

Answer 11

Psolution = Xsolvent*Psolvent
Psolution = vapor pressure of the solution
Xsolvent = mole fraction of the solvent (divide the number of moles of one component in the solution by the total number of moles in the solution as a whole)
Psolvent =vapor pressure of the pure solvent
Typically used when asked to find vapor pressure

Question 12

Osmotic Pressure

Answer 12

π = MRTi
M = molarity
R = 0.08206 L atm/mol K
T = Temperature
i = Van’t Hoff Factor