Unit 2 SCS #1-12 (pg. 180)

1. Matter is neither created nor destroyed. 

2. Scientific laws summarize what has been learned by careful observations of nature. 

3. Those expressions are misleading because they make it seem like atoms are being "used up" or "thrown away" when they actually just become rearranged into different molecule. 

4. a. Reaction: Sn: 1   H: 1   F: 1
        Product: Sn: 1   H: 2   F: 2
        This equation is not balanced.
    b. Reaction: Si: 1    O: 2    C: 1
        Product: Si: 1    O: 1    C: 2
        This equation is not balanced. 
    c. Reaction: Al: 1    O: 3    H: 6    Cl: 3
        Product: Al: 1    O: 3    H: 6    Cl: 3
        This equation is balanced. 

5. a. 3
    b. 2
    c. 1

6. a. 1, 3, 1, 3
    b. 1, 1, 1, 1
    c. 4, 3, 2

7. a. 1, 3, 2, 3
    b. 2, 10, 16, 18

8. a. Reactants: Na = 2
                         S = 1
                         O = 4
                         K = 2
                         Cl = 1
         Products: Na = 2
                         S = 1
                         O = 4
                         K = 2
                         Cl = 1
     b. The student didn't create a properly balanced equation since he/she added atoms instead of adding coefficients to the substance. 
     c. 1, 2, 2, 1

9. Approximately 2,000,000 years. 

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

11. 1 mole of the substance is 63.6 grams of copper and 23.0 of sodium metal. 

12. a. 6.02 x 10^23
      b. 3.01 x 10^23
      c. 0.602 x 10^23
      d. 0.154 x 10^23