2SCS #1-12 pg. 180

1. The law of conservation of matter 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 conservation of matter, molecules can be converted and decomposed by chemical processes.

4.a. Not balanced.

Reactant side: Sn, 1, H, 1, F, 1
Product side: Sn, 1, H, 2, F; 2
b. Not balanced. 
Reactant side: Si, 1, O, 2, C, 1
Product side: Si, 1, O, 1, C, 2
c. Balanced. 
Reactant side: Al, 1, O, 3, H, 6, Cl, 3
Product side: Al, 1, O, 3, H, 6, Cl, 3

5.a. hydrogen gas is 3.
b.  NH3 gas is 3. 
c. nitrogen gas is 1. 

6.?

7. a. 1 Ca3(PO4)2 + 3 H2SO4 --> 2 H3PO4 + 3 CaSO4

b. 2 C8H18 + 25 O2 --> 16 CO2 + 18 H2O

8. a. Yes. 
Reactant side: Na, 2, S, 1, O, 4, K, 2, Cl, 1
Product side: Na, 2, S, 1, O, 4, K, 2, Cl, 1
b. No 
c. 1 Na2SO4 + 2 KCl --> 2 NaCl + 1 K2SO4

9. it would take 400,000 seconds to spend one mole of dollars.

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

11. Although copper and sodium have different masses, volumes, and densities, the weight of each atom per mole remains the same. 

12.a. 1 atom.
b. 0.5 atoms. 
c. 0.1 atoms. 
d.  0.03 atoms.