Empirical and Molecular Formulas Quiz

What is the primary difference between an empirical formula and a molecular formula?

• Molecular formula is always the same as the empirical formula.

• Empirical formula shows the simplest whole number ratio of atoms.

• Molecular formula shows the simplest whole number ratio of atoms.

• Empirical formula shows the actual number of atoms in a molecule.

Which of the following is both the empirical and molecular formula for carbon dioxide?

• C3O6

• CO

• CO2

• C2O4

In the sample problem, what is the first step in determining the empirical formula from percent composition?

• Determine the molecular formula.

• Convert percent to grams.

• Find the smallest mole ratio.

• Convert grams to moles.

How do you convert grams to moles in the context of finding an empirical formula?

• Subtract the atomic mass unit (AMU) from the periodic table.

• Divide by the atomic mass unit (AMU) from the periodic table.

• Multiply by the atomic mass unit (AMU) from the periodic table.

• Add the atomic mass unit (AMU) from the periodic table.

What is the empirical formula for a compound with 71.65% chlorine, 24.27% carbon, and 4.077% hydrogen?

• C1H2Cl1

• CH2Cl

• C3H6Cl3

• C2H4Cl2

In the aspirin example, what is the first step to find the empirical formula?

• Convert grams to moles.

• Determine the molecular formula.

• Convert percent to grams.

• Find the smallest mole ratio.

What is the empirical formula for aspirin if it contains 60% carbon, 4.5% hydrogen, and 35.5% oxygen?

• C9H8O4

• C8H7O3

• C12H10O6

• C6H5O3

When dealing with fractional atom values, what should you do if you have a value of 0.25?

• Multiply by 5

• Multiply by 4

• Multiply by 3

• Multiply by 2

If you have a fractional value of 0.5 in your empirical formula, what should you multiply by to get a whole number?

• 3

• 5

• 2

• 4

What is the final empirical formula for aspirin after adjusting for fractional atom values?

• C9H8O4

• C7H6O3

• C8H7O3

• C10H9O5