EXERCISE 8-2 Percent Composition, Empirical and Molecular Formulas
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1
Calculate the mass percent of oxygen in carbon dioxide.
36.36%
66.67%
72.71%
None of the previous answers.
2
Calculate the mass percent of carbon in methanol (CH
4
O).
41.39%
37.49%
25.00%
33.33%
None of the previous answers.
3
Calculate the mass percent of hydrogen in methanol (CH
4
O).
12.58%
15.38%
22.22%
3.145%
None of the previous answers.
4
Calculate the mass percent of carbon in aspirin (C
9
H
8
O
4
).
60.00%
42.85%
57.44%
None of the previous answers.
5
Calculate the mass percent of oxygen in aspirin (C
9
H
8
O
4
).
19.05%
34.04%
35.52%
None of the previous answers.
6
Calculate the mass percent of calcium in calcium nitrate.
39.26%
24.42%
30.35%
15.38%
None of the previous answers.
7
Calculate the mass percent of nitrogen in calcium nitrate.
17.07%
13.71%
8.57%
None of the previous answers.
8
Calculate the mass percent of oxygen in calcium nitrate.
47.02%
58.50%
63.96%
None of the previous answers.
9
Calculate the mass percent of nitrogen in ammonium sulfide.
27.95%
41.11%
36.84%
None of the previous answers.
10
What is the mass percent of water in calcium chloride dihydrate?
24.51%
12.26%
32.46%
None of the previous answers.
11
Determine the empirical formula of a compound that consists of 79.88% copper and 20.12% oxygen by mass.
Cu
2
O
CuO
Cu
4
O
Cu
2
O
3
None of the previous answers.
12
Determine the empirical formula of a compound that consists of 68.42% chromium and 31.58% oxygen by mass.
CrO
2
CrO
CuO
3
Cr
2
O
3
None of the previous answers.
13
Determine the empirical formula of a compound that consists of 72.36% iron and 27.64% oxygen by mass.
FeO
2
FeO
Fe
3
O
4
Fe
2
O
3
None of the previous answers.
14
Determine the molecular formula of a compound that consists of 92.26% carbon and 7.74% hydrogen by mass and has a molecular mass of about 78 g/mol.
C
12
O
CH
C
6
H
6
None of the previous answers.
15
Determine the molecular formula of a compound that consists of 30.44% nitrogen and 69.55% oxygen by mass and has a molecular mass of about 91 g/mol.
NO
2
NO
N
2
O
N
2
O
4
None of the previous answers.
16
Determine the molecular formula of a compound that consists of 9.93% carbon, 58.64% chlorine and 31.43% fluorine by mass and has a molecular mass of about 121 g/mol.
CCl
2
F
2
CClF
CCl
6
F
3
None of the previous answers.
17
Determine the molecular formula of a compound that consists of 40.00% carbon, 6.71% hydrogen and 53.29% oxygen by mass and has a molecular mass of about 180 g/mol.
C
2
H
4
O
2
C
6
H
12
O
6
CH
2
O
None of the previous answers.
18
The mass percent of water in a hydrate of manganese(II) chloride is 36.41%. What is the empirical formula of the hydrate?
MnCl
2
.
H
2
O
MnCl
2
.
6 H
2
O
MnCl
2
.
4 H
2
O
None of the previous answers.
19
A 2.500 gram sample of a hydrate of calcium sulfate loses 0.523 grams of water when heated. Determine the formula of the hydrate.
CaSO
4
.
2 H
2
O
CaSO
4
.
4 H
2
O
CaSO
4
.
H
2
O
None of the previous answers.
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