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.

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

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.

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

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!

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: =

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

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:

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

PRACTICE 1. Mg 3 Bi 2 ▫Magnesium: 3 ▫Bismuth: 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

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.

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

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: CHECK POINT!

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: CHECK POINT!

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

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