Chemistry: Lecture 4: Solutions

Front 1

Colloid

Back 1

Like a solution, only the solute particles are larger. Too small to be extracted by filtration but usually large enough or charged enough to be separated by a semipermeable membrane (dialysis). They can also scatter light.

Front 2

Electrolytes

Back 2

Compounds that form ions in aqueous solution.

Front 3

Molarity (M)

Back 3

moles of solute / volume of solution

Front 4

Molality (m)

Back 4

moles of solute / kilograms of solvent

Front 5

Mole Fraction (X)

Back 5

moles of solute / kilograms of solvent

Front 6

Mass Percentage (%)

Back 6

(mass of solute / total mass of solution) * 100

Front 7

Parts Per Million (ppm)

Back 7

(mass of solute / total mass of solution) * 1,000,000

Front 8

Normality

Back 8

Measures the number of equivalents per liter of solution. (In an acid-base reaction, an equivalent is defined as the mass of acid or base that can furnish/accept one mole of protons)

Front 9

3 Steps to Solution Formation

Back 9

1) breaking of intermolecular bonds btwn solute molecules
2) breaking of intermolecular bonds btwn solvent molecules
3) the formation of intermolecular bonds btwn solvent and solute

Front 10

T or F: Energy is required to break a bond

Back 10

True

Front 11

A negative heat of solution results in:

Back 11

stronger intermolecular bonds

Front 12

A positive heat of solution results in:

Back 12

weaker intermolecular bonds

Front 13

When solutions form, entropy _________.

Back 13

increases

Front 14

Vapor Pressure

Back 14

The pressure created by molecules in open space when the rate of molecules leaving the liquid equals the rate of molecules entering the liquid, and equilibrium has been established. (gas and liquid phase in eq.)

Front 15

What is vapor pressure a function of?

Back 15

Temperature

Front 16

Vapor pressure ___________ with temperature

Back 16

increases

Front 17

Boiling

Back 17

Occurs when the vapor pressure of a liquid equals the atmospheric pressure.

Front 18

Melting

Back 18

Occurs when the vapor pressure of the solid phase equals the vapor pressure of the liquid phase.

Front 19

Nonvolatile Solute

Back 19

-A solute with no vapor pressure

Vapor pressure of the solution is given by Raoult's Law:

Pv = X*Pa

Pv = vapor pressure of soln
Pa = vapor pressure of pure liquid

Front 20

Volatile Solute

Back 20

-A solute with vapor pressure

Vapor pressure of the solution is given by Raoult's Law(2):

Pv = Xa*Pa + Xb*Pb

Front 21

Read Pages 72-73

Back 21

(On Chemistry Solutions)

Front 22

Precipitation

Back 22

Reverse reaction of dissolution, takes place initially at a slower rate.

Front 23

Saturated Solution

Back 23

As the salt dissolves and the conc of dissolved salt builds, the rate of dissolution and precipitation equilibrate = SATURATED

Front 24

Solubility Product (Ksp)

Back 24

-Use just like any other equilibrium expression (leave out pure solids and liquids)
-Depends only on temperature

Front 25

For most salts, crystallization is ____________(endo/exothermic)

Back 25

exothermic

Front 26

What does solubility depend on?

Back 26

The temperature and the ions in the solution.

Front 27

Solubility

Back 27

The maximum number of moles of the solute that can dissolve in solution (usually in mol/L)

Front 28

Spectator Ions

Back 28

Added ions in a solution that are not part of the equilibrium expression, and therefore have no effect

Front 29

Common Ions

Back 29

-An ion common to an ion in the equilibrium expression
-If added to a saturated solution, it will shift the eq, increasing precipitate, but doesn't affect the Ksp
-A common ion added to an unsaturated solution will NOT change the equilibrium

Front 30

Solubilities of ionic compounds containing nitrate and alkali metals

Back 30

All ionic compounds containing nitrate, ammonium, and alkali metals are soluble

Front 31

Ionic compounds containing halogens are _________, EXCEPT for __________, _________, and _______ compounds

Back 31

soluble, silver, mercury, and lead compounds

Front 32

Sulfate compounds are ______, EXCEPT for _______, ______, and the __________

Back 32

soluble, mercury, lead, heavier alkaline metals (Hg, Pb, Ca, etc)

Front 33

Compounds containing the heavier alkaline metals are ________ when paired with ______ and _______

Back 33

soluble, sulfides, hydroxides

Front 34

Carbonates, phosphates, sulfides, and hydroxides are generally __________

Back 34

insoluble

Front 35

Read Page 77

Back 35

Chemistry (Solutions)

Front 36

The solubility of a gas is proportional to:

Back 36

Vapor Partial Pressure (When we open a can of soda, solubility of gas decreases causing some gas to rise out of solution)

Front 37

As the temperature increases, the solubility of salts generally ___________

Back 37

increases

Front 38

As temperature increases, the solubility of gases ________

Back 38

decreases

Front 39

T or F: Heavier, larger gases experience greater covalent forces and tend to be less soluble

Back 39

FALSE: Van der Waals forces, more soluble