2SCS: p.181 #13-21

13. a. 6 moles NH3 are needed to react with 9 mol PbO.
b. 5 moles N2 are produced by the reaction of 10 mol NH3.
c. 5 moles Pb are produced from 5 mol PbO.

14. a. 1 mol N2 can be produced from 34.0 g NH3. 

b. 621 g Pb can be produced from the complete reaction of 3.0 mol PbO.
c. 28 g N2 can be produced from 34.0 g NH2.
d. 415 g PbO, which fully reacts, will produce 415 g Pb. 

15. Due to the percent of the oxygen atoms being 67%, since oxygen's molar mass is 32 and carbon's molar mass is 12 in this molecule, the percent oxygen by mass 32g/44g x 100%, or 73%. 

16. a. 

molar masses: Ag, 216g; S, 32g
216+32=248. 216g/248g x 100%= 
87% silver by mass
b.
molar masses: Al, 54g; O, 48g
54+48=102. 54g/102g x 100%=
53% aluminum by mass
c. 
molar masses: Ca, 40g; C, 12g; O, 48g
40+12+48=100. 40g/100g x 100%=
40% calcium by mass

17. a.

molar masses: Pb, 207g; S, 32g; O, 64g
207+32+64=303. 207g/303g x 100%= 
68% lead by mass
b. 
5g/50g x 100%=
10% PbSO4 in the ore sample. c. 
68 x .10= 
6.8% Pb in the total ore sample. d.

18. a. Reusing is when you use the same product more than 1 time for the same thing, but recycling means the product is used again but for another reason or purpose.

b. Reusing- Clothes and Containers

Recycling- Old computer parts and Composed piles

19. a. Solar energy, biomass, wood, and natural gas

b.  Coal, fossil fuels, food oil/petroleum, and gas

20. a. Reusing

b. Recycling

c. Recycling

21.  A light bulb can only be recycled but a newspaper could be reused and recycled for different things.