Chem 2 Exam 1, Ch 11

Front 1

molarity

Back 1

-M

Front 2

mass percent

Back 2

-aka weight percent

Front 3

mole fraction

Back 3

-X

Front 4

molality

Back 4

-m

Front 5

normality

Back 5

-N

-number of equivalents per liter of solution

-acid-base, divide by the number of H+ ions

-redox, divide by number of e-

Front 6

enthalpy (heat) of solution (delta H soln)

Back 6

-may be positive (energy absorbed, endo)

-may be negative (energy released, exo)

-steps 1 and 2 are usually endo, step 3 is usually eco

Front 7

formation of liquid solution enthalpy

Back 7

Front 8

energy and the formation of solutions

Back 8

-smaller enthalpies have a higher chance of forming solutions

Front 9

Henry's law

Back 9

-amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution.

-C: concentration of dissolved gas

-k: constant characteristic of a particular solution

-P: partial pressure of gaseous solute above the solution

Front 10

Raoult's Law, non volatile

Back 10

-Psoln is the observed vapor pressure of the soln

-Xsolv is the mole fraction of the solvent

-P0solv is the vapor pressure of the pure solvent

Front 11

Raoult's Law, volatile

Back 11

Front 12

raoult's law deviations

Back 12

-negative deviation: lower vapor pressure than predicted, strong interactions

-positive deviation: higher vapor pressure than predicted, weak interactions

Front 13

raoult's law deviations and relation to enthalpy

Back 13

-negative: large amounts of energy released due to strong interactions

-positive: small amounts of energy released due to weak interactions

Front 14

boiling point elevation

Back 14

a nonvolatile solute elevates the boiling point of the solvent

Front 15

common k constants for boiling and freezing

Back 15

Front 16

freezing point depression

Back 16

Front 17

osmotic pressure

Back 17

Front 18

isotonic solution

Back 18

solutions that have identical osmotic pressures

Front 19

van't hoff factor

Back 19

-The expected value for i can be calculated for a salt by noting the number of ions per formula unit. For example, for NaCl, i is 2; for K2SO4, i is 3; and for Fe3(PO4)2, i is 5.

-van't hoff factor is used for salts, not non electrolytes

-weak acids only don't have it

Front 20

Expected and observed van't hoff factors

Back 20

-van't hoff factor is used for salts, glucose is a non electrolyte

Front 21

Enthalpy calculation for solutions

Back 21

aq - solid

-negative is exo, solubility decreases as temp rises

-positive is endo, solubility increases as temp rises

Front 22

cubic centimeter

Back 22

equivalent to a mL

Front 23

solubility

Back 23

-ionic compounds dissolve readily in water

-the longer the hydrocarbon chain, the more non polar it is

-water is polar

Front 24

hydration in an aqueous solution

Back 24

-Interactions between the water molecules and ions are stronger with smaller ions.

-Interactions between the water molecules and ions increases as the charge on the ions increase.

Front 25

how to find empirical formulas

Back 25

1. find the percent of the total of each atom

2. multiply by 100g

3. multiply by the molecular weight of the atom

4. round to the nearest integer

Front 26

how to find molecular formulas

Back 26

1. compare molecular weight of the empirical formula against a determined molecular weight

2. multiply the empirical formula by the multiple difference