2SCS #1-12 p180

1. The law of conservation of matter is in a chemical equation matter can neither be created nor destroyed.

2. A scientific law summarizes what has been learned by careful observation of nature.

3. You can never use up or throw away any matter at all according to the law of conservation of matter.

4. a) Reactants: Sn-1 H-1 F-1 Products: Sn-1 H-2 F-2 =unbalanced
b) Reactants: Si-1 O-2 C-1 Products: Si-1 O-1 C-2 =unbalanced
c) Reactants: Al-1 O-3 H-6 Cl-3 Products: Al-1 O-3 H-6 Cl-3 =balanced

5. a) 3
b) 2
c) 1

6. See Drawings
a) 1WO3+3H2----> 1W+3H2O
b) 2PbS+3O2----> 2PbO+2SO2
c)4Fe+3O2----> 2Fe2O3

7. a)1-3-2-3
b) 2-25-16-18

8. a) Na-2 S-1 O-4 K-2 Cl-1-------Na-2 S-1 O-4 K-2 Cl-1
NO
b) No, she added and took away subscripts from the original equation which cannot be done.
c) 1Na2SO4+2KCl---->2NaCl+1K2SO4

9. ??????????????????????????????

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

11. Moles are a representation of atoms which is a quantity and does not vary from element to element.

12. a) 6.02 x 1023 atoms
b) 3.01 x 1023 atoms
c) .1 atoms
d) ??????