Chapter 13: Physical Properties of Solutions Flashcards
Saturated solutions
Solutions with the maximum possible amount of dissolved solute
Solubility
The amount of solute dissolved in a saturated solution (in a specified solvent, at a specified temperature)
T increase = increase in solubility of most solids in water
T increase = decreases solubility of most gases in water
P increase = increase in solubility of most gases in water (no effect on solids in water)
Unsaturated solutions
Solutions that contain less than the maximum possible amount of solute
Supersaturated solutions
Solutions that contain more solute than specified by the solubility
Miscible
Substances with similar intermolecular forces tend to be soluble in one another (regardless of amount of solute?)
Effect of entropy on forming a solution
An increase in entropy (ΔS) drives solution formation
Solvation
Process when solute particles are surrounded by solvent molecules
Molality
m = moles of solute / kg of solvent
Percent by mass
Mass of solute divided by total mass of solution [not just the solvent!] (multiplied by 100)
(w/W)
*When no units such as (w/W), percent by mass is assumed
Henry’s law
The solubility of a gas in a liquid is directly proportional to the partial pressure of gas over the solution
Henry’s law constant (k) is specific to the gas and solvent, and are temperature dependent
Colligative properties
Properties which depend on the number of dissolved particles (type is negligible)
Such properties include:
Vapor-pressure lowering
Boiling-point elevation
Freezing-point depression
Osmotic pressure
Volatile vs. nonvolatile
Volatile = substance with a measurable vapor pressure
Nonvolatile = substance with NO measurable vapor pressure
Raoult’s law
States that the partial pressure of a substance over a solution is equal to the mole fraction of the substance times its pure vapor pressure (P°)
PA = P° / XA
*Ideal solutions obeys this law
