Solutions C12, pp

Types of Mixtures Solute (dissolved substance) Solvent (dissolving medium) Homogeneous – Solutions (any state of matter) Heterogeneous – Colloids  milk, glue, paint, fog, emulsions, foam – Suspensions  muddy water – pizza, granite, stews,

Distinguishing Properties Particle size – 0.01 – 1 nm = solution – nm = colloid – nm = suspension Filtration – Suspensions only Tyndall effect (light scattering) – Heterogeneous mixtures only

Factors Affecting Dissolution Increase solute’s surface area exposure – Pulverize Increase # of solute-solvent collisions – Agitate solution – Heat solution Disperse solute molecules – Agitate – Heat

Solubility Unsaturated – Contains less than maximum amount of solute Saturated – Contains maximum amount of solute Supersaturated – Contains more dissolved solute than saturated at the same conditions – Create by dissolving at increased temperature

Solute-Solvent Interactions “Like dissolves like.” – Polar or ionic solutes in polar solvents – Nonpolar solutes in nonpolar solvents – Soap has polar AND nonpolar ends Pressure – Increases gas solubility in liquids Henry’s Law – Solubility of gas in liquid directly proportional to partial pressure of that gas above the liquid

Enthalpies of Solution Formation of solution occurs with energy  Negative enthalpy = exothermic – Energy is released – Dissolution of gases in liquids – Formation of NaOH, KOH, HCl, HI, NH 3, CH 3 COOH Positive enthalpy = endothermic – Energy is absorbed – Formation of KI, KCl, NaCl, NaNO 3, MgSO 4, AgNO 3

Concentrations of Solutions Molarity (M) – Moles of solute / Liters of solution Molality (m) – Moles of solute/ kilograms of solvent Moles of solute – Grams of solute/ molar mass of solute Molar mass is calculated from periodic table – Density of solute x volume = grams (Grams/ mL)(mL) = grams; cm 3 = cc = mL for liquids