Chapter 13: Physical Properties of Solutions Flashcards
solution
a homogeneous mixture of two or more substances; consists of a solvent and one or more solutes.
unsaturated solution
one that contains less solute than the solvent has the capacity to dissolve at a specific temperature
saturated solution
one that contains the maximum amount of solute that will dissolve in a solvent at a specific temperature
Supersaturated solutions
contain more dissolved solute than is present in a saturated solution and are generally unstable
Solvation occurs when
solute molecules are separated from one another and surrounded by solvent molecules.
entropy
a measure of how dispersed or spread out its energy is.
There is a natural tendency for the energy of a system to
become dispersed (entropy increases).
Two substances with similar type and magnitude of intermolecular forces are likely to be _____ in each other
soluble
Two liquids are said to be ____ if they are completely soluble in each other in all proportions.
miscible
concentration
The amount of solute relative to the volume of a solution or to the amount of solvent in a solution
Molality
the number of moles of solute dissolved in 1 kg (1000 g) solvent
Pressure greatly influences
the solubility of a gas.
Henry’s law states that
the solubility of a gas in a liquid is proportional to the pressure of the gas over the solution.
Colligative properties
properties that depend on the number of solute particles in solution
The colligative properties are:
Vapor pressure lowering.
Boiling point elevation.
Freezing point depression.
Osmotic pressure.
Raoult’s law states that
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.
If both components of a solution are volatile:
the vapor pressure of the solution is the sum of the individual partial pressures
ideal solution
obeys Raoult’s law.
Solutions boil at a _____ temperature than the pure solvent.
higher
Solutions freeze at a _____ temperature than the pure solvent.
lower
Osmosis
the selective passage of solvent molecules through a porous membrane from a more dilute solution to a more concentrated one.
Osmotic pressure
pressure required to stop osmosis
Electrolytes undergo ______ when dissolved in water.
dissociation
van’t Hoff factor
accounts for electrolyte dissociation
The van’t Hoff factor (i) is ____ for all nonelectrolytes
1
For strong electrolytes i should be equal to _____
the number of ions
The van’t Hoff factor (i) is usually smaller than predicted due to
formation of ion pairs
ion pair
made up of one or more cations and one or more anions held together by electrostatic forces.
Percent dissociation
is the percentage of dissolved molecules (or formula units, in the case of an ionic compound) that separate into ions in a solution and this can be found using colligative properties
Percent dissociation of a strong electrolyte is more complete at ______ concentration.
lower
Percent ionization of weak electrolytes is also dependent on
concentration
colloid
a dispersion of particles of one substance throughout another substance. (Colloid particles are much larger than the normal solute molecules.)
colloid examples
Aerosols. Foams. Emulsions. Sols. Gels.
Colloids with water as the dispersing medium can be categorized as
hydrophilic (water loving) or hydrophobic (water fearing).
Hydrophobic colloids can be stabilized by the presence of
hydrophilic groups on their surface (think hyrdophilic head)
Emulsification
the process of stabilizing a colloid that would otherwise not stay dispersed
