Chem 108 Ch. 12

Front 1

In the case of a solution of a gas or solid dissolved in liquid, it is the gas or solid, in other cases, it is the component in smaller amount.

Back 1

Solute

Front 2

In a solution of a gas or solid dissolved in a liquid, this is the liquid, in other cases, it is the components in the greater amount.

Back 2

Solvent

Front 3

When one substance dissolves in another it is said to be

Back 3

Soluble

Front 4

When one substance does not dissolve in another it is said to be

Back 4

Insoluble

Front 5

Fluids that mix with or dissolve in each other in all proportions are said to be

Back 5

Miscible

Front 6

Fluids that do not dissolve in each other are said to be

Back 6

Immiscible

Front 7

This solution is in equilibrium with respect to the amount of dissolved solute. The rate at which the solute leaves the solid state equals the rate at which the solute returns to the solid state.

Back 7

Saturated

Front 8

A solution not in equilibrium with respect to a given dissolved substance and in which more of the substance can be dissolved

Back 8

Unsaturated

Front 9

A solution that contains more dissolved substance than a saturated solution does. This occurs when a solution is prepared at higher temperature and is then slowly cooled. This is a very unstable situation, so any disturbance causes precipitation, such as "seeding" with a crystal.

Back 9

Supersaturated

Front 10

Solutes dissolve in solvents that have the same type of intermolecular forces, "like dissolves like"in these solutions

Back 10

Molecular solutions

Front 11

To make a solution you must:

1. Overcome all attractions between the solute particles. ∆Hsolute is endothermic

2. Overcome some attractions between solvent molecules. ∆Hsolution is endothermic

3. Form new attractions between solute particles and solvent molecules. ∆Hmix is exothermic

Back 11

The overall ∆H for making a solution depends on the relative sizes of the ∆H for these three processes.

∆Hsolution = ∆Hsolute + ∆Hsolvent +∆Hmix

Front 12

The energy released when one mole of the ionic compounds forms from its free ions in the gas phase (M+(g) + X-(g) = MX (s)) Depends on ionic charge and ionic radius.

Back 12

Lattice Energy

U = k(Q1Q2)/d

K is constant based on lattice structure

Front 13

Energy required to remove ions from the crystal lattice is the dissolution of ionic solids.

Back 13

∆Hion-ion = -U (lattice energy)

∆Hsol'n = ∆Hion-ion + ∆Hhydration

Front 14

Algebraic sum of enthalpy changes associated with formation of ionic solid from constituent elements

Back 14

Born-Haber Cycle

Front 15

When dissolving absorbed heat (is endothermic), the temperature of the solution decreases as the solubility as the solute dissolves.

Back 15

The solubility will increase as temperature increases. Ex: Cold pack

Front 16

When dissolving releases heat (is exothermic), the temperature of the solution increases as the solute dissolves.

Back 16

The solubility will decrease as the temperature increases. Ex: Hot pack

Front 17

The solubility of a sparingly soluble chemically unreactive gas is proportional to the partial pressure of the gas: Cgas = (kH)(Pgas)

C is the concentration of gas in solution, kH is the constant for the gas, and Pgas is the partial pressure of gas.

Or Sgas = (kH)(Pgas) where S is the solubility.

Back 17

Henry's Law

Front 18

Solubility of alcohols

Back 18

Decreases as relative energy of H-bonding decreases and dispersion increases

Front 19

Process to separate volatile components of a mixture.

Back 19

Fractional Distillation

Front 20

Properties that depend of the concentration of the solute molecules or ions in solution but not on the chemical identity of the solute.

Back 20

Colligative properties

Front 21

What happens to the properties of a substance when there is solute in the substance?

Back 21

Vapor-pressure lowering

Boiling-point elevation

Freezing-point lowering

Osmotic pressure

Front 22

The partial pressure of solvent, Pa, of a solution equals the vapor pressure of the pure solvent, P°a, times the mole fraction of the solvent, Xa, in the solution. Pa = P°aXa

Back 22

Raoult's Law

Front 23

Moles of solute/kg of solvent

Back 23

Molality

Front 24

Boiling point elevation

Back 24

∆Tb = Kb • m (Kb is boiling pt elevation constant and m is molality

Front 25

Freezing point depression

Back 25

∆Tf = Kf • m (Kf is the freezing point depression constant, m = molality

Front 26

In solutions of electrolytes, you need to correct for the number of particles formed when ionic substance dissolves. Number of ions in the formula unit. NaCl = 2

Back 26

Van't Hoff Factor (i)

∆Tb = i•Kb•m

Front 27

Movement of solvent through semi-permeable membrane from region of low solute concentration to region of higher solute concentration

Back 27

Osmosis

Front 28

Pressure required to half flow of solvent through membrane due to osmosis

Back 28

Osmotic pressure (π)

π = iMRT

Front 29

Total solute concentration in the solution matches that inside the cell. Osmosis medical application

Back 29

Isotonic

Front 30

Total solute concentration in the solution greater than that inside the cell. Osmosis medical application

Back 30

Hypertonic

Front 31

Total solute concentration in the solution is less than that inside the cell. Osmosis medical application

Back 31

Hypotonic

Front 32

Use of high pressure to move solvent across membrane from region of high solute concentration to a region of lower solute concentration. Application: Desalination/water purification

Back 32

Reverse osmosis