Percent Composition, Empirical and Molecular Formula Question Trail

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 percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

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

• 24%
• 49%
• 51%
• 65%

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

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

• Cu₃O₈
• CuO₄
• Cu₂O
• Cu₄O₁₀

Which one is empirical?

• H₂O₂
• C₂H₆O₁₂
• CaCl₂
• N₂O₈

What is the empirical formula for the following molecular formula: C₆H₁₄

• C₆H₁₄
• C₃H₇
• CH₂
• CH₃

What is the molecular formula if the empirical formula is C₂H₅ and the molecular molar mass is 58.14 g/mol?

• C₂H₅
• C₄H₁₀
• C₁H_2.5
• C₄H₈

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

• C₂H₃O₂
• CH₂O
• C₂H₄O₂
• C₃H₈O₃