Calculating Molecular Formulas

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 for N₂S₃?

• NS

• N₃S₂

• N₂S₃

• N₁S_1.5

Tags

NGSS.MS-PS1-1

How many "C" are in CO₂

• 2

• 1

• 0

• 3

Tags

NGSS.MS-PS1-1

How many Carbons "C" are in C₁₈H₃₄O₃

• 18

• 34

• 3

• 37

Tags

NGSS.MS-PS1-1

What is the percent by mass of oxygen in MgO?

• 20%

• 40%

• 50%

• 60%

Which of the following could be a molecular formula with the empirical formula of CH₂O?

• CH₂O₂

• CHO

• C₃H₅O₃

• C₂H₄O₂

What is the empirical formula of K₂SO₄?

• K₂SO₄

• KSO₂

• K₂SO₂

• KSO₈

Tags

NGSS.HS-PS1-7

What is the percent by mass of sodium in NaCl?

• 39%

• 61%

• 35%

• 65%

Tags

NGSS.HS-PS1-7

What is the best definition for subscript?
 

• The big number that tells you the number of molecules.

• The atomic number

• The little number that tells the number of atoms for each element.

Tags

NGSS.MS-PS1-1

Gives the actual number of atoms of each element in a molecule of a compound.

• Empirical Formula

• Molecular Formula

• Stoichiometry

• Chemical Reaction