% Compositions, Empirical & Molecular Formulas

C₄H₆

• CH

• CH₃

• C₂H₃

• C₄H₆

Hg₂Br₂

• HgBr

• Hg₂Br₂

S₂O₈

• S₂O₈

• SO

• SO₄

• S₈O₂

C₂₅H₄₅

• C₂₅H₄₅

• CH

• C₅H₉

• C₉H₅

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%
• 49%
• 51%
• 65%

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

• 20%
• 27%
• 46%
• 53%

Tags

NGSS.HS-PS1-7

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

What is the molecular formula if the empirical formula is CH₂O and the 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