Pg 181 #13-17
13. For the equation
3 PbO(s) + 2 NH3(g) => 3 Pb(s) + N2(g) + 3 H2O(l)
a. How many moles NH3 are needed to react with 9 mol PbO?
i. 6 moles
b. How many moles N2 are produced by the reaction of 10 mol NH3?
i. 5 moles
c. How many moles Pb are produced from 5 mol PbO?
i. 5 moles
14. For the equation in Question 13,
a. How many moles (maximum) N2 can be produced from 34.0 g NH3?
i. 17 moles
b. What mass Pb can be produced from the complete reaction of 3.0 mol PbO?
i. 9 moles
c. What maximum mass N2 can be produced from 34.0 g NH3?
i. 28 grams N2
d. What mass PbO, which fully reacts, will produce 415 g Pb?
i. 669 grams PbO
15. In carbon dioxide, two-thirds of the atoms are oxygen atoms; however, the percent oxygen by mass is not 67%. Explain.
a. This is because you have to divide the number of oxygen atoms by the total number of atoms in the compound which ends up with 72% oxygen atoms.
16. Find the percent metal (by mass) in each of the following compounds:
a. Ag2S:
i. 87% metal (silver)
b. Al2O3:
i. 53% metal (aluminum)
c. CaCO3:
i. 40% metal (Calcium)
17. A 50.0-g sample of ore contains 5.00 g lead(II) sulfate, PbSO4:
a. What is the percent lead (Pb) in PbSO4?
i. 68% lead
b. What is the percent PbSO4 in the ore sample?
i. 10% lead(II) sulfate
c. What is the percent Pb in the total ore sample?
i. 7% lead
d. Use a diagram to represent the proportions of lead and lead(II) sulfate in the ore.
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