Physical Science Mrs. Baker Solutions Physical Science Mrs. Baker

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

Definitions Solute - KMnO4 Solvent - H2O

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

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

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

Rate of Solution Gases dissolve faster… high pressure low temperature

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

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

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

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

Colligative Properties Freezing Point Depression View Flash animation.

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

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

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

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

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

Concentration Percent by mass is grams of solute per total grams of solution. Molarity is number of moles (how we count chemical substances) per Liter of solution.

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

Solubility Solubility Curve shows the dependence of solubility on temperature

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