1. Difference between Physical and Chemical Changes

2. Physical and Chemical changes 1. Physical changes are reversible 1. Water can 1. freeze and melt over and over 2. Chemical changes are permanent 1. You can’t “2.unbake” a cake 3. Physical changes each substance keeps its own properties 1. If you 3.mix metal chips and 4.sand, the metal chips are still 5.magnetic. 2. If 6.salt and sand are mixed together, salt will still 7.dissolve in water.

3. 4. Chemical reaction a 7.completely new substance is formed 5. Example of chemical changes 1. Suntan, 8.rust, cooking anything 6. Example of physical changes 1. 9.Melting ice, salt and pepper mixed together 2. Boiling water

4. 1. Mixture 1. Substances mixed together, but 10.not chemically bound together. 2. Colloid a. A 11.mixture that is not see through. 1. Stays mixed 2. Examples a. 12.Mustard, ketchup, m ilk, mayo

5. 3. Suspension a. 13.Doesn’t stay mixed b. 14.Can’t see through it c. Examples 1. Lake water, 15.orange juice, paint, salad dressing 4. Solution a. 16.Stays mixed b. 17Transparent (can see through it) c. Close to a chemical reaction, but it isn’t!! d. Examples a. Sugar water, 18.Kool Aid, salt water, tea, coffee

6. 5. Parts of a solution a. Solvent 1. Part the 19.does the dissolving 2. The 20.water in sugar water (the liquid) b. Solute 1. Part that 21.is dissolved (the solid) 2. The 22.sugar in sugar water c. Mixed together so completely, it is 23.almost a chemical reaction

7. Chemical Reactions 1. 24.Permanent change 2. 25.New Substance formed 3. Chemical bonds Types 1. 26.Ionic bonds a. 27.One element will take e- from another element b. One atom will become 28.positive (losing the e-) c. One atom will become 29negative (gaining the e-) d. 30Transition Metals often use ionic bonds (Tall columns) H Cl

8. 6. Covalent Bonding a. The atoms 31.share e- b. One side of the molecule will be 32positive the other will be 33negative

9. 7. Pooling of electrons a. 34Metal elements pool e- b. That’s why they are so “35bendy” c. That’s why they 36conduct electricity and heat d. H O H AuAuAuAu 1. There’s a 37path for the heat or electricity to follow

10. Chemical Formulas 1. Capital letter = 38.Element a. Count the number of 39CAPITAL letters to tell the number of elements 2. Subscript (40little number) a. 41Tells the number of atoms in a molecule 3. Coefficient (42Big number) a. 43.Tells the total number of molecules b. Distributive property 6H2O= 2 elements (Hydrogen and Oxygen) = 6 molecules of water = total of 12 Hydrogens and 6 Oxygens