Calculating Molecular Formulas

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

• 24%

• 49%

• 51%

• 65%

What is the molar mass of PbSO₄

• 303.3 g/mol

• 294.7g/mol

• 163.8g/mol

• 372g/mol

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

Phenyl magnesium bromide is used as a reagent in organic synthesis. Determine its molecular formula if its molar mass is 181.31 g/mol and it contains 39.75% C, 2.78% H, 13.41% Mg, and 44.07% Br (these are in the correct order).

• C₁₂H₁₀Mg₂Br₂

• CHMgBr

• C₆H₅MgBr

• C₃H_2.5MgBr

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

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

Molecular formula mass = 192

Molecular Formula = ?

• C₄F₈

• C₄F

• CF₈

• C₂F₄

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 120?

• CH₂O

• C₂H₄O₂

• C₄H₈O₄

• C₆H₁₂O₆

What is the molecular formula for a compound with the empirical formula: CaCl₂ and a molecular mass of 220g.

• Ca₂Cl₄

• Ca₃Cl₆

• Ca₃Cl₉

• Ca₃Cl₅

A compound has the molar mass of 170.0 g/mol and an empirical formula of SiF₃. The compounds molecular formula is

• SiF₃

• Si₂F₆

• Si₅F₁₅

• Si₄F₁₂