Empirical formulas, molecular formulas, and percent composition

What is the percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

What is the percent by mass of chlorine in NaCl?

• 39%
• 61%
• 35%
• 65%

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 composition by mass of magnesium in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%

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

• 20%
• 27%
• 46%
• 53%

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 empirical formula for C₄H₆?

• CH

• CH₃

• C₂H₃

• C₄H₆

C₂F₆

Choose the correct empirical formula...

• CF

• C₂F₆

• C₆F₂

• CF₃

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

• SO

• SO₂

• SO₃

• SO₄