Empirical Formula Calculation Quiz

What is the first step in calculating an empirical formula?

• Multiply mole values to get whole numbers.

• Divide each mole value by the smallest number of moles.

• Start with the mass in grams of each element.

• Convert grams to moles using molar mass.

In Example 1, what is the empirical formula for the compound containing calcium, oxygen, and hydrogen?

• CaOH

• Ca(OH)2

• CaO2H2

• Ca2H2O2

When given percentages of elements, what assumption is made to simplify calculations?

• Assume a 100g sample.

• Assume a 50g sample.

• Assume a 1g sample.

• Assume a 200g sample.

What is the empirical formula for NutraSweet based on the given percentages?

• C14H18N2O4

• C14H18N2O5

• C7H9N2O5

• C7H9N1O2.5

What should you do if a mole value ends in 0.5 during calculations?

• Leave it as is.

• Multiply all mole values by 3.

• Multiply all mole values by 2.

• Round it to the nearest whole number.

In Example 3, what is the smallest number of moles calculated for the elements in magnetite?

• 1.2 moles

• 0.68 moles

• 1.33 moles

• 0.902 moles

What is the empirical formula for magnetite?

• Fe2O3

• FeO2

• FeO

• Fe3O4

What is the molar mass of oxygen used in these calculations?

• 18.00 g/mol

• 15.99 g/mol

• 16.00 g/mol

• 17.00 g/mol

Why is it important to convert grams to moles in empirical formula calculations?

• To determine the molecular formula.

• To compare the relative amounts of each element.

• To ensure the elements are balanced.

• To simplify the calculation process.

What should you do if a mole value ends in 0.33 during calculations?

• Round it to the nearest whole number.

• Multiply all mole values by 2.

• Multiply all mole values by 3.

• Leave it as is.