Empirical/Molecular Formula Review

What is the percent composition by mass of sulfur in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%

What is the empirical formula if you have 88.80% copper and 11.20% oxygen?

• Cu₃O₈

• CuO₄

• Cu₂O

• Cu₄O₁₀

What is the empirical formula if you have 36.84% nitrogen and 63.16% oxygen?

• NO

• N₂O₃

• N₂O₄

• N₂O₅

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180.18?

• CH₂O

• C₂H₄O₂

• C₄H₈O₄

• C₆H₁₂O₆

What is the molecular formula for a compound with the empirical formula: K₂SO₄ and a molecular mass of 696g.

• K₂SO₄ 

• K₈SO₁₆

• K₈S₄O₈ 

• K₈S₄O₁₆