Determining Empirical Formulas from Percent Composition

What does an empirical formula represent?

• The exact number of atoms in a molecule

• The lowest whole number ratio of elements in a compound

• The molecular weight of a compound

• The percentage composition of elements

What is the first step in determining the empirical formula from percent composition?

• Divide by the smallest number of moles

• Assume a 100 gram sample

• Find the molecular formula

• Convert grams to moles

Why do we assume a 100 gram sample when calculating empirical formulas?

• To simplify the calculation

• To convert moles to grams

• To find the molecular formula

• To determine the molecular weight

In the example with sulfur and oxygen, what is the empirical formula of the compound?

• SO2

• S2O2

• SO

• S2O

What is the molecular mass of sulfur used in the example?

• 32.06 grams per mole

• 12.01 grams per mole

• 16.00 grams per mole

• 1.01 grams per mole

In the example with carbon, hydrogen, and oxygen, what is the empirical formula of the compound?

• C6H12O6

• CH2O

• C2H5O

• C4H10O

What is the molecular mass of carbon used in the example?

• 1.01 grams per mole

• 16.00 grams per mole

• 12.01 grams per mole

• 32.06 grams per mole

What is the final step in determining the empirical formula?

• Convert grams to moles

• Assume a 100 gram sample

• Divide by the smallest number of moles

• Find the molecular formula

Why is it important to determine the empirical formula?

• To find the exact number of atoms in a molecule

• To determine the percentage composition

• To calculate the molecular weight

• To understand the simplest ratio of elements in a compound

What is the empirical formula of glucose?

• CHO

• C2H4O2

• CH2O

• C6H12O6