Empirical and Molecular Quiz with Mass to Moles

Which pair of molecules would have the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇

• C₂H₄O₂ and C₆H₁₂O₆

• C₃H₆O₃ and C₂H₆O₂

• CH₄ and C₂H₆

What is the empirical formula of C₄H₆ ?

• CH

• CH₃

• C₂H₃

• C₄H₆

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

• 20%
• 27%
• 46%
• 53%

How many moles are in 19.82 g Mg?

• 1.23 mol Mg

• 481.70 mol Mg

• 1.00 mol Mg

• 0.82 mol Mg

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 empirical formula if you have 81.82% carbon and 18.18% hydrogen?

• C3H8
• CH4
• C2H2
• C4H10

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180.18?

• CH₂O
• C₂H₄O₂
• C₄H₈O₄
• C₆H₁₂O₆

When calculating the Empirical Formula the mole ratio is given as follows:
H₁O_{3.5
What will the Empirical Formula be?}

• H₁O_3.5
• HO_3.5
• HO₄
• H₂O₇

A chemical formula that shows the actual # and kinds of atoms present in one molecule of a compound is called_________

• ionic formula
• covalent formula
• empirical formula
• molecular formula

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