Practice Test for % Composition by Mass and Empirical Formulas

1  What is the number of grams of sulfur in 100 grams of sulfuric acid (table K)?

2  What is the % composition by mass of the elements in ammonia (table L)?

3  What is the % composition by mass of iron in FeO?

4  What is the molar mass of (NH₄)₃PO₄ ?

5  How many grams of oxygen are in 324 grams of carbon monoxide?

6  What is the % composition by mass of silicon in SiO₃?

7  What are the representative particles for each of these compounds?
      NaCl            CO₂               MnCl₇            NH₃         I₄O₁₀         BF₃

8  What are the empirical formulas for these compounds?
        C₁₀H₂₀        C₁₂H₂₄O₁₂        C₁₀₀H₂₀₀O₁₀₀           C₂H₈O₂         C₆H₁₈O₁₂

9  How many grams of Al in 408.0 grams of Al₂O₃?

10  How many grams of oxygen are in 43.0 liters of sulfur trioxide?

11  If you have 7.42 x 10²⁸ particles of HF gas, how many grams of fluorine do you have?

12  How many atoms in each?
          (NH₄)₃PO₄       Hg₂(C₂H₃O₂)₂          NaOH              H₂SO₄