1-12 p. 180

1. Law of Conservation of Matter: matter is neither created nor destroyed in any chemical reaction or physical change.

2. Scientific Law: summarizes what has been learned by careful observation of nature.

3. They are misleading because "using up"and "throwing away" sound the opposite of the law of conservation of matter, which is that no matter in created nor destroyed. "Using up" means that materials are chemically changed, not destroyed.

4. a. Reactants Sn: 1, H:1, F:1  Products: Sn:1, F: 2, H:2 This equation is not chemically balanced.
   b. Reactants Si: 1, O: 2, C: 1 Products: Si: 1, C: 2, O: 1 This equation is not chemically balanced.
   c. Reactants Al: 1, O: 3, H: 6, Cl: 3 Products: Al: 1, O: 3, H: 6, Cl: 3 This equation is chemically balanced.

5. a. 3
    b. 2
    c. 1

6. a. 1 WO₃ + 3 H₂ ---à 1 W + 3 H₂0
    b. 2 PbS + 3 O₂  ---à 2 PbO + 2 SO₂
    c. 4 Fe + 3 O₂ ---à 2 Fe₂O₃

7. a. 1 Ca₃ (PO₄)₂ + 3H₂SO₄ ---à 2H₃PO₄ + 3CaSO₄
      b. C₈H₁₈ + 13O₂ ---à 8CO₂ + 9H₂0

8. a. Na: 2, S:1, O: 4, K:2, Cl:1---> Na:2, S:1, O: 4, K: 2, Cl: 1
    b. Yes

9. 5

10. a. 32g
      b. 48g
      c. 100g
      d. 58g
      e. 180g

11. They can both represent a mole because a mole is just the amount of an element that you can use in a lab.

12. a. 19 atoms
      b. 9.5 atoms
      c. 1.9 atoms
      d. 1 atom