Percent Composition, Empirical Formulas, and Molecular Formulas

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

• K₂SO₄ 
• K₈SO₁₆
• K₈S₄O₈ 
• K₈S₄O₁₆ 

What is the molecular formula of a compound with an empirical formula of C₂OH₄ and a molar mass of 88 grams per mole?

• C₂O₄H₈
• C₈O₂H₄
• C₄O₂H₈
• C₄O₈H₂

Find the percent composition of N₂S₂.

• N: 69.6%  S: 30.4%
• N:36% S: 75.6%
• N: 96.6% S: 3.4%
• N: 30.4% S: 69.6%

222.6 g of Sodium combine completely with 77.4 g of Oxygen. What is percent composition of Sodium and Oxygen?

• 25% Sodium, 74.2% Oxygen
• 15% Sodium, 85% Oxygen
• 74.2% Sodium, 25.8% Oxygen
• 90% Sodium, 10% Oxygen

Tags

NGSS.HS-PS1-7

Find the percent composition of Cu in CuBr₂ .   

• 28.45%
• 32.85%
• 17.78%
• 68.10%

What is the empirical formula of a molecule containing 18.7% of Lithium, 16.3% of Carbon and 65.0% of oxygen?

• CO₂Li₃
• Li₂CO₃
• Li₃CO₂
• LiCO₅

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

• NO
• N₂O₃
• N₂O₄
• N₂O₅

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements. (keep two decimal places throughout calculations)

• SO
• SO₂
• SO₃
• SO₄

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

• CH₂O
• C₂H₄O₂
• C₄H₈O₄
• C₆H₁₂O₆

Find the percentage composition of  Mg in Mg₃(PO₄)₂.
   

• 27.75% Mg
• 23.57% Mg
• 48.68% Mg
• 13.45% Mg