Empirical Formulas

Find the empirical formula for each of the following substances.  The percent composition is given.

1.  88.8 % copper & 11.2 % oxygen

2.  10.04 % carbon, 0.84 % hydrogen, & 89.12 % chlorine

3.  42.50 % chromium & 57.50 % chlorine

4.  38.67 % potassium, 13.85 % nitrogen, & 47.48 % oxygen

5.  72.40 % iron & 27.60 % oxygen

Part 2 – Determine the empirical formula of the following compounds using the given data.

6.  Find the empirical formula for sodium sulfite.  Sodium sulfite contains 36.5 % sodium,
25.4 % sulfur, and 38.1 % oxygen.

7.  What is the empirical formula for a compound which contains 53.73 % iron and 46.27 %
sulfur?

8.  What is the empirical formula of a compound if the percentage composition is:
aluminum 15.77 %, sulfur 28.11 %, and oxygen 56.12 %?

9.  If 8.87 grams of phosphorus react with 11.43 grams of oxygen, what is the empirical
formula of the compound formed?

10.  Phosgene, a poisonous gas used during World War I, contains 12.1 % C, 16.2 % O, and
71.7% Cl.  What is the empirical formula for phosgene?