Key Terms
Solution
A homogeneous mixture uniform at the molecular level. Solvent: the component present in greatest concentration; determin
Exothermic dissolution
NaCl in water (solvation forces exceed ionic forces) Endothermic dissolution: NH4NO3 in water (ionic forces exceed solva
Electrolyte
Dissolves in water to produce ions; conducts electricity in solution. Nonelectrolyte: dissolves without producing ions;
Example
HCl(g) + H2O → H3O+ + Cl- This reaction is essentially 100% complete; HCl is a strong acid and a strong electrolyte.
Solubility
Maximum concentration of solute achievable at equilibrium under given conditions. Saturated: solute concentration equals
Miscible
Completely soluble in all proportions (ethanol + water)
Immiscible
Negligible mutual solubility (oil + water) Partially miscible: moderate mutual solubility (bromine + water)
Temperature effect on gases
Gas solubility DECREASES as temperature increases. Warmer water holds less dissolved oxygen — this is the mechanism behi
Equation
Delta-Tf = Kf x m
Most solids
Solubility increases with temperature. Exception: some ionic compounds (like cerium sulfate) show decreasing solubility
Water
Kf = 1.86 degrees C/m Benzene: Kf = 5.12 degrees C/m
Real-world uses
Road salt, antifreeze in radiators, seawater staying liquid below 0 degrees C.
Semipermeable membrane
Allows solvent through, blocks solute. Osmosis: net movement of solvent from low-solute-concentration side to high- solu
Isotonic
Same osmotic pressure as the reference solution (e.g., blood serum ~7.7 atm). Safe for IV injection.
Corrected equations
Delta-Tb = i x Kb x m delta-Tf = i x Kf x m Pi = i x MRT