Empirical/Molecular formulas

What is the percent by mass of oxygen in MgO?

• 20%

• 40%

• 50%

• 60%

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

• 20%

• 27%

• 46%

• 53%

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇

• C₂H₄O₂ and C₆H₁₂O₆

• C₃H₆O₃ and C₂H₆O₂

• CH₄ and C₂H₆

A formula with the lowest whole # ratio of elements in a compound is called

• Molecular Formula

• Chemical Formula

• Empirical Formula 

• Distance Formula

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 

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇

• C₂H₄O₂ and C₆H₁₂O₆

• C₃H₆O₃ and C₂H₆O₂

• CH₄ and C₂H₆

An empirical formula:

• is a formula that calculates the coefficients of a compound in a balanced equation.

• is the simplest whole-number ratio of moles of elements in the compound.

Which of the following is considered an empirical formula?

• CH₃COOH

• C₆H₁₂O₆

• H₂O

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

• SO

• SO2

• SO3

• SO4