2SCS pg.180-181 #1-12

1) The law of conversations of mater is that matter is neither created nor destroyed.

2) Scientific law summarizes what has been learned by careful observation of nature.

3) Expressions such as "using up" and "throwing away" are misleading because the law of coversation of matter states that matter is neither created nor destroyed and "using up" and "throwing away" seem like the atoms are dissapearing when they are actually just being rearranged into a different molecule. 

4) 
a. Not balanced
Sn-1    Sn-1
H-1      H-2
F-1      F-2
b. Not balanced
Si-1     Si-1
O-2     O-1
C-1      C-2
c. Balanced
Al-1    Al-1
O-3    O-3
H-6    H-6
Cl-3   Cl-3

5) 
a. The coefficient for hydrogen gas is 3. 
b. The coefficient for NH3 gas is 2. 
c. The coefficient for nitrogen gas is 1. 

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

7) 
a. 1, 3, 2, 3 
b. 2, 25, 16, 18

8) 
a. 
Na-2    Na-2
S-1      S-1
O-4     O-4
K-2      K2
Cl-1     Cl-1
b. No, because the student added/changed the subscripts and subscripts are supposed to stay the same. 
c. 1, 2, 2, 1

9) It would take 19,000,000 years. 

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

11) 63.6 g copper metal and 23.0 g of sodium metal both correctly represent 1.00 mol. 

12) 
a. 1 atom. 
b. .5 atoms.
c. .1 atoms.
d. .03 atoms.