WorksheetsPercent Composition Practice Problems 1
Total questions: 15
Worksheet time: 2hrs 30mins
Name
Class
Date
1.
What is the percent composition by mass of sulfur in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
2.
What is the percent composition by mass of oxygen in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
3.
What is the percent composition of Benzene, C6H6?
a)
C = 50%
H = 50%
H = 50%
b)
C = 85.7 %
H = 14.3%
H = 14.3%
c)
C = 92.2%
H = 7.8%
H = 7.8%
d)
C = 71.9%
H = 28.1%
H = 28.1%
4.
What is the percent composition of aluminum phosphate?
a)
Al = 25%
P = 25%
O = 75%
P = 25%
O = 75%
b)
Al = 22.1%
P = 35.8%
O = 42.1%
P = 35.8%
O = 42.1%
c)
Al = 14.3%
P = 25.4%
O = 60.3%
P = 25.4%
O = 60.3%
d)
Al = 22.1%
P = 25.4%
O = 52.5%
P = 25.4%
O = 52.5%
5.
What percent of Zn3(PO4)2 is zinc?
a)
33.15%
b)
16.04%
c)
50.80%
d)
19.68%
6.
What is the percent by mass of Mn in KMnO4?
a)
50%
b)
25%
c)
35%
d)
40%
7.
What is the percent by mass of O in NaOH?
a)
40%
b)
2.5%
c)
22.9%
d)
57.5%
8.
How many oxygen atoms are in Mg(NO3)2?
a)
2
b)
3
c)
5
d)
6
9.
How many H atoms are in (NH4)3PO4?
a)
4
b)
7
c)
12
d)
15
10.
What is the percent by mass of O in (NH4)3PO4?
a)
8%
b)
43%
c)
12%
d)
21%
11.
What is the percentage of chromium in K2Cr2O7?
a)
38.1%
b)
27.2%
c)
34.7%
d)
100%
12.
What is the percent composition of water?
a)
H = 11.1%
O = 89.9%
O = 89.9%
b)
H = 66.7%
O = 33.3%
O = 33.3%
c)
H = 5.6%
O = 89.9%
O = 89.9%
d)
H = 20%
O = 80%
O = 80%
13.
Carbon monoxide, a deadly gas, has a chemical formula of CO (one carbon atom with one oxygen atom). If you look at the total atomic mass of CO, does carbon or oxygen make up more of the mass?
a)
carbon
b)
oxygen
c)
they are exactly the same
d)
it is impossible to tell
14.
What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?
a)
29%
b)
43%
c)
57%
d)
73%
15.
What is the percent by mass of N in (NH4)2S?
a)
47.1%
b)
68.1%
c)
44.1%
d)
41.1%
100 %
