Name: ____________________________________ Period: ________ Date: ________ Score:_________
Empirical/Molecular Formula Practice Worksheet
Directions:
Find the empirical
AND molecular
formulas given the percent compositions or
masses.
SHOW YOUR WORK
to receive full credit.
1) 26.4 % Carbon 3.3 % Hydrogen 70.3 % Oxygen Molar Mass: 91.0 g/mol
Empirical Formula:_________________ Molecular Formula:_________________
2) 81.8 grams Carbon 18.2 grams Hydrogen Molar Mass: 132.0 g/mol
Empirical Formula:_________________ Molecular Formula:_________________
3) 20.2 % Sodium 37.6 % Sulfur 42.2 % Oxygen Molar Mass: 682.8 g/mol
Empirical Formula:_________________ Molecular Formula:_________________
4) 8.81 g Carbon 91.2 g Chlorine Molar Mass:1362.5 g/mol
Empirical Formula:_________________ Molecular Formula:_________________
5) Determine the empirical and molecular formula of a compound composed of 18.24 g Carbon,
0.51 g Hydrogen, and 16.91 g Fluorine has a molar mass 562.0 g/mol.
Empirical Formula:_________________ Molecular Formula:_________________
6) A compound with a molar mass of 544.0 g/mol is made up of 26.5 grams Carbon, 2.94 grams
Hydrogen, and 70.6 grams Oxygen. What is its empirical and molecular formula?
Empirical Formula:_________________ Molecular Formula:_________________
7) The percent composition of an unknown substance is 75.42 % Carbon, 6.63 % Hydrogen,
8.38 % Nitrogen, and 9.57 % Oxygen. If its molar mass is 334.0 g/mol what is its empirical and
molecular formula?
Empirical Formula:_________________ Molecular Formula:_________________
