6. Given 6 mol of each reactant, which one would be limiting in the following reaction?
4Au + 8NaCN + O
2
+ 2H
2
O
→
4NaAu(CN)
2
+ 4NaOH
a.
Au
b.
NaCN
c.
O
2
d.
H
2
O
e.
There is no limiting reactant.
7. In the direct reaction of silicon with Cl
2
the yield of SiCl
4
is 50. %. How many grams
of silicon must be reacted with excess chlorine in order to obtain 17 g SiCl
4
?
a.
1.4 g
b.
2.8 g
c.
5.6 g
d.
17 g
e.
28 g
8. In the reaction of Fe
3
O
4
with carbon to form carbon dioxide and iron, the number of
moles of carbon required to convert 23 g of Fe
3
O
4
to products is
a. 0.05
b. 0.1
c. 0.2
d. 0.3
e. 0.4
9. A 20.0 mL sample of an element with a density of 3.0 g/mL contains 4 x 10
23
atoms.
What is the atomic weight of this element?
a. 300
b. 40
c. 60
d. 90
e. none of the above
10. How many moles of oxygen gas will react with 12.4 mol aluminum?
Equation: 4Al + 3O
2
→
2Al
2
O
3
a. 0.24 mol
b. 0.42 mol
c. 4.8 mol
d. 9.3 mol
e. 16.8 mol
