WorksheetsFormula Mass, % Composition, EF & Molecular Formula Quiz # 1
Total questions: 22
Worksheet time: 6hrs 30mins
Find formula mass of Mg3(PO4)2.
363.97
262.87
335.8
238.5
Find the formula mass of N2S2 .
23
46
92.16
86.99
What is the empirical formula if you have 36.84% nitrogen and 63.16% oxygen?
NO
N2O4
N2O3
N2O5
You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements. (keep two decimal places throughout calculations.)
SO
SO2
SO3
SO4
Empirical formula for C4H6
CH
CH3
C2H3
C4H6
Empirical Formula for Br2O6
BrO3
Br6O2
BrO
Br2O6
Empirical Formula for P2O6
P2O6
PO
PO3
P3O
Empirical Formula for C25H45
C25H45
CH
C5H9
C9H5
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.
20%
40%
50%
60%
Formula mass of K2S
110.3
109
78.2
111.2
A compound is found to contain 63.52 % iron and 36.48% sulfur. Find its empirical formula.
Fe2S3
F2S3
FeS
F2S
What is the empirical formula for a compound containing 38.8% carbon, 16.2% hydrogen, and 45.1% nitrogen?
C2H10N2
C2H5N
CH5N
C3H5N2
A hydrocarbon is a compound comprised of carbon and hydrogen atoms. An unknown hydrocarbon is found to contain 85.7% carbon and an formula mass of 84.0 g/mol. What is its molecular formula?
CH2
C3H6
C6H12
C4H8
A piece of iron ore is found to contain a compound containing 72.3% iron and 27.7% oxygen with a formula mass of 231.4 g/mol. What is the molecular formula of the compound?
Fe2O3
Fe3O4
Fe4O5
FeO2
