Solution Chemistry and Solubility 12A—Demonstrate and explain effects of temperature and the nature of solid solutes on the solubility of solids 13A—Compare unsaturated, saturated, and supersaturated solutions 13B—Interpret relationships among ionic and covalent compounds, electrical conductivity, and colligative properties of water

Review  Element—substance that cannot be broken down into simpler substances (periodic table)  Compound—a substance made of atoms of more than one element bound together (H 2 O, CO 2, NaCl)  Mixture—a combination of more than one pure substance (Salt water, Powerade, Salad)

Mixture Review  Mixture—a physical blend of two or more substances  Heterogeneous mixture—one that is not uniform in composition  Homogeneous mixture—one that has a completely uniform composition

Mixture Review

Mixture REVIEW  You can separate mixtures by PHYSICAL means Distillation Separation Chromatography

TypeParticle size Settle upon standing Tyndall effect (Scatter light) SolutionsHomo- geneous nmNono ColloidHetero- geneous nmNoYes SuspensionHetero- geneous Greater than 1000 nm Yessometimes

Solution Chemistry  Solution—a homogeneous mixture  Solute—dissolved particles in a solution  Solvent—the dissolving medium in a solution (usually water, the universal solvent)

Kool-Aid Solution  Kool-Aid Juice is the SOLUTION  Kool-Aid powder and Sugar are the SOLUTES  Water is the SOLVENT

Soluble vs. Insoluble  Soluble—dissolves completely so that solution looks transparent (free of any floating particles  Insoluble—does not dissolve completely; solution is cloudy

How does dissolving takes place?  What happens when salt is dissolved in water? What happens when salt is dissolved in water? NaCl  Na + + Cl -

Complete the dissociation of the following salts:  KCl  K + + Cl -  MgCl 2  Mg Cl -  AlCl 3  Al Cl -  MgF 2  Mg F - **

Solution Chemistry  Electrolytes—compounds that conduct an electric current ALL ionic compounds; NaCl, CuSO 4, NaOH  Nonelectrolytes—Compounds that do not conduct an electric current in either aqueous solution or the molten state Many molecular compounds; carbon, sugar, alcohol

Electrolytes vs. Nonelectrolytes

 Some very polar molecular compounds are nonelectrolytes in pure state but become electrolytes when dissolved in water  NH 3 (g) + H 2 O(l)  NH 4 + (aq) + OH - (aq)

Electrolytes vs. Nonelectrolytes  Weak Electrolyte—only a fraction of the solute exists as ions  Strong Electrolyte—almost all the solute exists as separate ions

Weak Electrolyte in solution. Strong electrolyte in solution.

Electrolytes vs. Nonelectrolytes  STRONG ELECTROLYTES Strong acids (HCl, H 2 SO 4, HNO 3 ) Strong bases (NaOH, KOH)  WEAK ELECTROLYTES Weak acids (Vinegar, acetic acid, CH 3 COOH) Weak bases (Ammonia, NH 3 )  NONELECTROLYTES Molecular compounds Nonmetal bonded to nonmetal

Electrolytes vs. Nonelectrolytes  More ions in solutions, the more conductivity  Which salt would give more ions: NaCl or MgCl 2 ?  So, which will conduct electricity more/be a better electrolyte?  Look back at the dissociation reactions and determine the better electrolyte.dissociation reactions

Solutions are homogeneous mixtures that could be solid, liquid, or gaseous Gas Oxygen in nitrogen GasLiquidCO 2 in water LiquidGasWater in air Liquid Alcohol in water LiquidSolidMercury in silver and tin (dental amalgam) SolidLiquidSugar in water Solid Copper in nickel (alloys)

Solubility  Solubility—the amount that dissolves in a given quantity of a solvent at a given temperature to produce a saturated solution. Solubility is often expressed in grams of solute per 100g of solvent

Water and Solubility?  REMEMBER water is a POLAR molecule Polar means electrons are not spread evenly throughout the molecule  Polar molecules dissolve polar molecules Water can dissolve ammonia  Nonpolar molecules dissolve nonpolar molecules Octane (gasoline) can dissolve CO 2  LIKE DISSOLVES LIKE!!!!

Solution Concentration  Concentration—the quantity of solute dissolved in a given quantity of solution Three ways to describe a solution Unsaturated solution Saturated solution Supersaturated solution

Solubility  Unsaturated—a solution that contains less solute than solvent  Saturated—a solution that contains the maximum amount of solute for a given amount of solvent at a constant temperature  Supersaturated—a solution that contains more solute than it can theoretically hold at a given temperature; crystals form

Solubility  Two liquids are said to be MISCIBLE if they dissolve in each other Water and ethanol dissolve in each other  Liquids that are insoluble in each other are IMMISCIBLE. Oil and water do no dissolve in each other

MISCIBLE Water and alcohol IMMISCIBLE Water and oil

Gas Solubility  Henry’s Law—as the pressure of the gas above the liquid increases, solubility of the gas increases and vice versa

Gas Solubility  Henry’s Law  S = solubility  P = Pressure S1S2P1P2S1S2P1P2 =

Gas Solubility  EXAMPLES Ears Popping Underwater Diving (the bends) Airplane taking off or landing

Factors Affecting Solubility  SURFACE AREA Solutes with larger surface area dissolves faster Smaller pieces dissolve faster than larger pieces

Factors Affecting Solubility  STIRRING Stirring or shaking a solution helps the solute dissolve faster Stirring or shaking moves dissolved sugar away from undissolved sugar crystals

Factors Affecting Solubility  TEMPERATURE Solutes dissolve faster when the solvent is hot When substance is heated, particles move faster causing more collisions between particles

Factors Affecting Solubility  Things that dissolve in water are called SOLUBLE  Things that do not dissolve in water are called INSOLUBLE

Solubility Curves  Solubility curves (graphs) give the solubility and temperature of a saturated solution.  Solubility is on y-axis  Temperature (°C) is on x-axis

Solubility Curve

Solubility Curves  SATURATED solution is ON line or curve  UNSATURATED solution is BELOW line or curve  SUPERSATURATED solution is above line or curve