2. Review What’s the difference between a pure substance and a mixture? What’s the difference between a mechanical mixture and a solution? Of mechanical mixtures and solutions, which are homogeneous and heterogeneous? Are solutions mixtures or pure substances? What kinds of states (of matter) can solutions be?

3. Definitions Dissolve: To mix one type of matter into another type of matter to form a solution Solvent: The larger part of a solution; the part on a solution into which the solute dissolves Solute: The smaller part of a solution; the part of a solution that dissolves in the solvent

4. Liquid Solutions Have liquid solvents Solvent Examples: Vegetable oil and water in food preparation (water and iced tea) Ethanol in perfume Turpentine in paint Ethyl acetate in nail polish

5. Liquid Solutions [Cont’d] Solutes that dissolve in liquids can be solids, liquids, or gases Solid examples: salt, sugar Liquid examples: acetic acid (combined with water for vinegar) Gas examples: carbon dioxide and nitrogen (dissolve in our blood) In salt water, solute =, solvent =

6. Solid Solutions In a solid solution, solute and solvent are solid Example: 14 carat gold = 14 parts pure gold and 10 parts other metals (silver, copper, nickel, palladium) (24 carat gold = pure gold) In this case, gold = solvent and other metals = solute

7. Solid Solutions [Cont’d] Alloys: solid solutions with two or more metals To make alloys: metals melted until they mix, then cooled down Examples: Brass = alloy of copper and zinc Bronze = alloy of copper and tin Solvent (in examples above)? Solutes?

8. Gas Solutions Solvent and solute are gases Examples: Air = 78% nitrogen, 21% oxygen, 1% argon gas, and smaller amounts of other gases Solvent? Solutes?