1. Do Now Identify if the following is a physical change or chemical change. 1)Cookie dough was put into the oven and the cookies are baking and rising in the pan. 2)Water molecules that stick together are… a)Polar b)Non-polar 3) Give an example of a mixture that is considered a suspension. Chemical Heterogeneous mixture - easy to see and separate material. Salad, trail mix, rocks in water.

2. Homework and Announcements Grading – Textbooks and notebooks Due: pgs 364-371 Today: USA TestPrep

3. Counting Atoms L.O. SWBAT describe the law of conservation of matter.

4. RULES FOR COUNTING ATOMS 1.SUBSCRIPTS only refer to the atom that they are to the right of. For example… H 2 S There are TWO atoms of HYDROGEN and only ONE atom of SULFUR.

5. Check Point MgCl 2 Atoms of Magnesium: Atoms of Chlorine: 1 2 Al 2 S 3 Atoms of Aluminum: Atoms of Sulfur: 2 3

6. COEFFICIENTS 2.COEFFICIENTS apply to the entire compound. You MULTIPLY the COEFFICIENTS and SUBSCRIPTS. 2 H 2 S ATOMS OF HYDROGEN: ATOMS OF SULFUR: 2 x 2 = 4 2 x 1 = 2 IF THERE ISN’T A SUBSCRIPT, THERE IS ONLY ONE ATOM OF THAT ELEMENT!

7. CHECK POINT 2H 2 SO 4 Atoms of Hydrogen: Atoms of Sulfur: Atoms of Oxygen: 4 2 3CH 3 OH Atoms of Carbon: Atoms of Hydrogen: Atoms of Oxygen: 3 9 + 3 = 12 8 3

8. PARENTHESES 3. If elements or compounds are inside of PARENTHESES, then the SUBSCRIPT to the right of the parentheses applies to everything inside. Ba(OH) 2 ATOMS OF BARIUM: ATOMS OF OXYGEN: ATOMS OF HYDROGEN: 1 2 2

9. THIS COULD BE A LITTLE TRICKY… Ca 3 (PO 4 ) 2 Atoms of Calcium: Atoms of Phosphorus: Atoms of Oxygen: 3 2 Al 2 (SO 4 ) 3 Atoms of Aluminum: Atoms of Sulfur: Atoms of Oxygen: 2 3 8 12

10. What about this BAD BOY??? 2Ca 3 (PO 4 ) 2 Atoms of Calcium: Atoms of Phosphorus: Atoms of Oxygen: 2 x 3 = 6 (2x1) x 2 = 4 (4 x 2) x 2 = 16

11. PRACTICE 1. Mg 3 Bi 2 ▫Magnesium: 3 ▫Bismuth: 2 2. 4 NaAu(CN) 2 ▫Sodium: 4 ▫Gold: 4 ▫Carbon: 8 ▫Nitrogen: 8 3. Challenge 5 Hg(BrO 3 ) 2 Mercury: 5 Bromine: 10 Oxygen: 30 Example: Co(OH) 2 Cobalt: 1 Oxygen: 2 Hydrogen: 2 Example: BaBr 2 Barium: 1 Bromine: 2

12. Conservation of Matter CH 4 + 2O 2 CO 2 + 2H 2 O (1 C, 4H, 4 O) In a chemical reaction atoms are not created or destroyed, they are only rearranged.

13. Mass of Reactants = Mass of Products Conservation of Matter Reactants → Products Example: H ₂ + O → H ₂ O Example: 10 g H ₂ + 15 g O → 25 g of H ₂ O

14. Fe + Cl 2  FeCl 3 What are the reactants? What are the products? Does this equation show conservation of matter? No Fe: Cl: Fe: Cl: 11 23 CHECK POINT!

15. 2Fe + 3Cl 2  2FeCl 3 What are the reactants? What are the products? Does this equation show conservation of matter? Yes Fe: Cl: Fe: Cl: 22 66 CHECK POINT!

16. Reactants:  Will be changed into new substance.  What you start with. Products:  New Substance formed  What you end up with. REACTANTS  PRODUCTS

17. Summary What 3-5 sentences discussing what you learned today.