Ch. 24 - Solutions I. How Solutions Form Definitions Types of Solutions Dissolving Rate of Dissolving

A. Definitions Solution - homogeneous mixture Solute - substance being dissolved Solvent - present in greater amount

A. Definitions Solute - KMnO4 Solvent - H2O

B. Types of Solutions Based on state of solvent. All solid-liquid-gas combos are possible. EX: dental amalgam (alloy of silver, mercury, etc.) liquid solute, solid solvent solid solution

C. Dissolving Solvation occurs at the surface of the solute solvent particles surround solute particles (+/- attraction) solute particles are pulled into solution

NaCl dissolving in water C. Dissolving NaCl dissolving in water

D. Rate of Solution Solids dissolve faster... more stirring small particle size (increased surface area) high temperature

D. Rate of Solution Gases dissolve faster... no shaking or stirring high pressure low temperature

II. Solubility & Concentration Ch. 24 - Solutions II. Solubility & Concentration

A. Concentration Concentrated solution large amount of solute Dilute solution small amount of solute

A. Concentration % by Volume usu. liquid in liquid EX: 10% juice = 10mL juice + 90mL water % by Mass usu. solid in liquid EX: 20% NaCl = 20g NaCl + 80g water

A. Concentration UNSATURATED SOLUTION more solute dissolves no more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form concentration

B. Solubility Solubility maximum grams of solute that will dissolve in 100 g of solvent at a given temperature varies with temperature based on a saturated solution

B. Solubility Solubility Curve shows the dependence of solubility on temperature

B. Solubility Solids are more soluble at... high temperatures. Gases are more soluble at... low temperatures. high pressures (Henry’s Law).

III. Particles in Solution Ch. 24 - Solutions III. Particles in Solution “Like Dissolves Like” Electrolytes Colligative Properties

A. “Like Dissolves Like” NONPOLAR POLAR Detergents polar “head” with long nonpolar “tail” can dissolve both types

B. Electrolytes Electrolyte Weak Electrolyte Non- Electrolyte + salt - + acetic acid - + sugar Electrolyte Weak Electrolyte Non- Electrolyte solute exists as ions only solute exists as ions and molecules solute exists as molecules only

B. Electrolytes Dissociation separation of +/- ions when an ionic compound dissolves in water

B. Electrolytes Ionization breaking apart of polar covalent molecules into ions when dissolving in water

C. Colligative Properties properties of solutions that depend only on solute concentration Freezing Point Depression solutes lower the f.p. of a solvent Boiling Point Elevation solutes raise the b.p. of a solvent

C. Colligative Properties Freezing Point Depression View Flash animation.

C. Colligative Properties Boiling Point Elevation Solute particles “get in the way.”

C. Colligative Properties Effect increases as the solute concentration increases. Uses: antifreeze making ice cream salting icy roads

IV. Intro to Acids & Bases Definitions Properties Uses Ch. 24 - Acids & Bases IV. Intro to Acids & Bases Definitions Properties Uses

HCl + H2O  H3O+ + Cl– A. Definitions Acids Ionize to form hydronium ions (H3O+) in water HCl + H2O  H3O+ + Cl–

NH3 + H2O  NH4+ + OH- A. Definitions Bases Dissociate or ionize to form hydroxide ions (OH-) in water NH3 + H2O  NH4+ + OH-

A. Definitions Indicator substance that changes color in an acid or base Examples: litmus - red/blue phenolphthalein - colorless/pink goldenrod - yellow/red red cabbage juice - pink/green

B. Properties ACIDS BASES sour taste corrosive electrolytes turn litmus red react with metals to form H2 gas bitter taste corrosive electrolytes turn litmus blue slippery feel

C. Uses ACIDS H3PO4 - soft drinks, fertilizer, detergents H2SO4 - fertilizer, car batteries HCl - gastric juice HC2H3O2 - vinegar

C. Uses BASES NaOH - lye, drain and oven cleaner Mg(OH)2 - laxative, antacid NH3 - cleaners, fertilizer

. Strength of Acids & Bases Strong vs. Weak pH Ch. 24 - Acids & Bases . Strength of Acids & Bases Strong vs. Weak pH

V. Intro to Acids & Bases Definitions Properties Uses Ch. 24 - Acids & Bases V. Intro to Acids & Bases Definitions Properties Uses

HCl + H2O  H3O+ + Cl– A. Definitions Acids Ionize to form hydronium ions (H3O+) in water HCl + H2O  H3O+ + Cl–

NH3 + H2O  NH4+ + OH- A. Definitions Bases Dissociate or ionize to form hydroxide ions (OH-) in water NH3 + H2O  NH4+ + OH-

A. Definitions Indicator substance that changes color in an acid or base Examples: litmus - red/blue phenolphthalein - colorless/pink goldenrod - yellow/red red cabbage juice - pink/green

B. Properties ACIDS BASES sour taste corrosive electrolytes turn litmus red react with metals to form H2 gas bitter taste corrosive electrolytes turn litmus blue slippery feel

C. Uses ACIDS H3PO4 - soft drinks, fertilizer, detergents H2SO4 - fertilizer, car batteries HCl - gastric juice HC2H3O2 - vinegar

C. Uses BASES NaOH - lye, drain and oven cleaner Mg(OH)2 - laxative, antacid NH3 - cleaners, fertilizer

A. Strong vs. Weak Strong Acid/Base 100% ions in water strong electrolyte HCl, HNO3, NaOH, LiOH - + Weak Acid/Base few ions in water weak electrolyte HC2H3O2, NH3 - +

B. pH Scale pH a measure of the concentration of H3O+ ions in solution measured with a pH meter or an indicator with a wide color range 7 INCREASING ACIDITY NEUTRAL BASICITY 14

pH of Common Substances B. pH Scale pH of Common Substances

ConcepTest Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA? A B

ConcepTest Is the following statement TRUE or FALSE? A strong acid has a lower pH than a weak acid. FALSE - Strong/weak refers to amount of ionization whereas pH refers to concentration of H+.

Ch. 24 - Acids & Bases VI. Neutralization Neutralization Reaction Titration

A. Neutralization Reaction Chemical reaction between an acid and a base. Products are a salt (ionic compound) and water.

A. Neutralization Reaction ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H2O = Neutralization does not always mean pH = 7.

A. Neutralization Reaction KOH + HNO3  H2O + KNO3 Acid? Base? Salt? HNO3 KOH KNO3

B. Titration standard solution unknown solution Titration Process in which a standard solution is used to determine the concentration of an unknown solution.

B. Titration Endpoint (equivalence point) Point at which equal amounts of H3O+ and OH- have been added. Determined by… indicator color change dramatic change in pH

VI. Naming Acids Definition Acid Names Acid Formulas Ch. 24 - Chemical Bonds VI. Naming Acids Definition Acid Names Acid Formulas

A. Definition Acid Compound that forms H+ in water. Formula usually begins with ‘H’. Examples: HCl, HNO3, H2SO4

B. Acid Names

B. Acid Names HBr H2CO3 -ide  hydrobromic acid H2SO3 -ate  carbonic acid -ite  sulfurous acid

C. Acid Formulas hydrofluoric acid sulfuric acid nitrous acid -ide  HF -ate  H2SO4 -ite  HNO2