Name:
Molecular Formulas Practice II
1. An analysis of a compound used in cosmetics revels the compound contains 26.76% C,
2.21% H, 71.17% O and has a molecular mass of 90.04 g/mol. Determine the molecular formula of the
sample.
2. The analysis of an unknown compound shows that is contains 83.15 % C and 16.85 % H. The molecular
mass is 72.10 g/mol. Determine the molecular formula of this compound.
3. Eucalyptus leaves are the food source for panda bears. Eucalyptol is an oil found in these leaves. Analysis
of eucalyptol indicates it has a molar mass of 154 g/mol and contains 77.87 % C, 11.76 % H, and 10.37 %
O. Determine the molecular formula of eucalyptol.
Empirical Formula Review
Find the empirical formula for each of the following substances. The percentage composition is given.
1. 88.8% copper; 11.2% oxygen
2. 40.0% carbon; 6.7% hydrogen; 53.3% oxygen
3. 92.3% carbon; 7.7% hydrogen
4. 70.0% iron; 30.0% oxygen
5. 5.88% hydrogen; 94.12% oxygen
6. 79.90% copper; 20.10% oxygen
7. 56.4% potassium; 8.7% carbon; 34.9% oxygen
8. 10.04% carbon; 0.84% hydrogen; 89.12% chlorine
9. 42.50% chromium; 57.50% chlorine
10. 15.8% carbon; 84.2% sulfur
Percent Composition Practice
Find the percent compositions of all of the elements in the following compounds:
1) CuBr2
Cu: ______
Br: ______
2) NaOH
Na: ______
O: ______
H: ______
3) (NH4)2S
N: ______
H: ______
S: ______
4) N2S2
N: ______
S: ______