Section 12.2
Usong Moles
Practice Test
1.
What is the mass of 0.100 mol of sodium chloride?
a.
0 g
b.
0.355 g
c.
0.585 g
d.
10.0 g
Hint
2.
How many moles of magnesium atoms is 7.32 × 10
26
atoms?
a.
1.22 × 10
3
mol
b.
6.02 × 10
3
mol
c.
8.23 × 10
26
mol
d.
4.44 × 10
1
mol
Hint
3.
80.0 g of butane burns according to the chemical equation 2C
4
H
10
+ 13O
2
8CO
2
+ 10H
2
O. What mass of oxygen reacts?
a.
1.28 kg
b.
32 g
c.
286 g
d.
416 g
Hint
4.
At STP, one molar volume is __________.
a.
22.4 L
b.
32.0 L
c.
10.0 L
d.
6.02 × 10
23
L
Hint
5.
What volume of HCl at STP can be produced by the reaction of 12.0 L of hydrogen and 24.0 L of chlorine, both at STP?
a.
12.0 L
b.
36.0 L
c.
24.0 L
d.
100.0 L
Hint
6.
According to the equation 2HBr + Na
2
CO
3
NaBr + H
2
O + CO
2
, what volume of CO
2
at 1.230 atm and 325 K is produced by 50.0 g of HBr reacting with an excess of Na
2
CO
3
?
a.
6.70 L
b.
22.4 L
c.
50.0 L
d.
1.52 L
Hint
7.
If the theoretical yield of a reaction is 0.2100 g and the actual yield is 0.1880 g, what is the percent yield?
a.
11.00%
b.
51.30%
c.
89.50%
d.
112%
Hint
8.
What is the volume of 3.66 mol of an ideal gas at 145 kPa and -23
o
C?
a.
52.4 L
b.
22.8 L
c.
100.6 L
d.
4.21 L
Hint
9.
2.52 g of diatomic oxygen occupies 3.00 L at 266 K. What is the pressure of the oxygen?
a.
58.0 kPa
b.
42.0 kPa
c.
33.5 Pa
d.
123 kPa
Hint
10.
What is the percent boron by mass in boric acid, H
3
BO
3
?
a.
17.50%
b.
22.10%
c.
38.00%
d.
45.30%
Hint
11.
What is the molar mass of potassium dichromate?
a.
88.3 g/mol
b.
102 g/mol
c.
176 g/mol
d.
294 g/mol
Hint
12.
What is the empirical formula of a compound that is 66.0% calcium and 34.0% phosphorus?
a.
Ca
3
P
2
b.
Ca
4
P
c.
CaP
3
d.
Ca
3
P
5
Hint
13.
The empirical formula for a compound is CH and its molar mass is 78 g/mol. What is the compound's molecular formula?
a.
C
6
H
6
b.
CH
c.
C
3
H
3
d.
C
10
H
10
Hint
14.
What is the theoretical yield of nitrogen gas if 200 g of sodium azide decomposes?
a.
127 g
b.
135 g
c.
200 g
d.
400 g
Hint
