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WorksheetsPercent Composition
Total questions: 11
Worksheet time: 52mins
Name
Class
Date
1.
What is the percent by mass of oxygen in MgO? Hint: The attached image is an example of a worked problem other than this one.
a)
20%
b)
40%
c)
50%
d)
60%
2.
What is the percent by mass of magnesium in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
3.
What is the percent by mass of fluorine in CaF2 (gram-formula mass = 78 g/mol)?
a)
24%
b)
49%
c)
51%
d)
65%
4.
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%
5.
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%
6.
In which compound is the percent composition by mass of Cl equal to 42%?
a)
HClO (gram formula mass = 52 g/mol)
b)
HClO2 (gram formula mass = 68 g/mol)
c)
HClO3 (gram formula mass = 84 g/mol)
d)
HClO4 (gram formula mass = 100 g/mol)
7.
Find the percent composition of Cu2S?
a)
%Cu= 67.987 %S= 32.013
b)
%Cu= 79.854 %S= 20.145
c)
%Cu= 35.946 %S= 64.054
8.
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%
9.
What is the empirical formula for the following:
Pb5Cr5O20
Pb5Cr5O20
a)
Pb2Cr2O10
b)
PbCr2O7
c)
Pb9Cr4O2
d)
PbCrO4
10.
Which element has an abundance of 39.03% in the compound sodium phosphate, Na3PO4
a)
Na
b)
P
c)
O
d)
None of the above
11.
Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?
a)
K
b)
C
c)
N
d)
None of the above
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