Chapter 13

Physical properties of solutions

solution

homogeneous mixture of two or more substances; consists of a solvent and two or more solutes

solubility

max amount of solute that will dissolved in a given amount of solvent at a specified temperature

unsaturated solution

solution that contains less solute than the solvent has capacity to dissolve at a specific temperature

saturated solution

solution that contains the maximum amount of solute that will dissolve in a solvent at a specific temperature

supersaturated solution

solution that contains more dissolved solute than is present in a saturated solution specific temperature; unstable

entropy

A measure of how many accessible states are available

solvation

when solute molecules are separated from one another and surrounded by solvent molecules

dipole-induced dipole

partial charge on a polar molecule induces temporary partial charge on neighboring nonpolar molecule

ion-induced dipole

charge of an ion induces a The temporary partial charge on a neighboring nonpolar molecule

two substances with similar type and magnitude IMF are likely to

be soluble in each other

miscible

two liquids are completely soluble in each other in all proportions

Vitamins C and B are soluble in

water

Vitamins A, D, E, and K are soluble in

non polar compounds

concentration

amount of solute relative to the volume of a solution or to the amount of solvent

molarity

M = moles of solute/liters of solution

mole fraction

X_A = moles of A/sum of moles of all compounds

percent by mass

mass of solute/mass of solute + mass of solvent x 100%

molality

m = moles of solute/mass of solvent (in kg)

solubility of solid solutes in liquid solvent ____ with increasing temperature

increases

solubility of a gas in a liquid solvent ____ with increasing temperature

decreases

solubility of liquids and solids ___ with pressure

does not change

Henry’s law definition

the solubility of a gas in a liquid is proportional to the pressure of the gas over the solution

henry’s law equation

C = KP

C

molar concentration (mol/L)

P

pressure (atm)

Henry’s law constant

K; proportionality constant (mol/L * atm)

colligative properties

properties that depend on the number of solute particles in a solution (not the nature of the solute)

types of colligative properties

vapor pressure, boiling point, freezing point, and osmotic pressure

Raoult’s law

the partial pressure of a solvent over a solution is given by the vapor pressure of the pure solvent times the mole fraction of the solvent in the solution

Raoult’s law formula

P_i = X_i * P^o

P_i

partial pressure of solvent/solution

P^o

vapor pressure of pure solvent

X_i

mole fraction of solvent

vapor pressure of a solution is __ than that of the pure solvent

lower

van’t Hoff factor

i; accounts for the effect of an electrolyte undergoing dissociation when dissolved in water

i

number of particles in solution after dissociation/number of formula units initially dissolved in solution

for all nonelectrolytes i =

1

for strong electrolytes, i =

the number of ions

ion pairs

made up of one or more cation and one or more anions held together by electrostatic forces

nonvolatile

solutes that don’t vaporize

__ has an affect on experimentally measured van’t Hoff factors

concentration

due to concentration, I is usually smaller than predicted due to the formation of

ion pairs

boiling point elevation equation

ΔT_b = iK * m

ΔT_b

boiling point elevation; boiling point of solution - boiling point of solvent

K_b

boiling point elevation constant (degrees C/m)

solutions freeze at ___ temperatures than the solvent

lower

osmosis

selective passage of solvent molecules through a porous membrane from a more dilute solution to a more concentrated one

osmotic pressure

π; pressure required to stop osmosis

in osmosis there is movement of solutes from an areas of ___ solvent concentrations to areas of ___ solvent concentrations

high to low

osmotic pressure equation

π = iMRT

freezing point depression equation

ΔT_f = iK * m

ΔT_f

freezing point depression; T_f-solvent - T_f-solution

K_f

freezing point depression constant (degrees C/m)

R

gas constant (L*atm/mol*K)

hypertonic

solute concentration outside the cell is greater (lower solvent concentration) than it is outside the cell

what happens to the cell if placed in a hypertonic solution

water flows out of the cell, it shrinks, and crenation occurs

hypotonic

solute concentration outside the cell is less (higher solvent concentration) than it is inside the cell

what happens to a cell it is placed in a hypotonic solution

water flows into the cell, the cell swells (eventually bursts), and hemolysis occurs

isotonic

equal amounts of solvents and solutes inside and outside the cell

an increase in solutes leads to a ____ in vapor pressure

decrease

an increase in solutes leads to a ____ in boiling point

increase

an increase in solutes leads to a ____ in freezing point

decrease

an increase in solutes leads to a ____ in osmotic pressure

increase