Empirical and Molecular Formulas

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of atoms of each element in a compound.

Front

What is a molecular formula?

Back

A molecular formula shows the actual number of atoms of each element in a molecule of a compound.

Front

How do you determine the empirical formula from percent composition?

Back

Convert the percentages to grams, then to moles, and find the simplest whole-number ratio of the elements.

Front

What is the empirical formula of a compound with 72.2% magnesium and 27.8% nitrogen?

Back

Mg3N2

Front

How many carbon atoms are in C18H34O3?

Back

18

Front

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

Back

C6H12O6

Front

What is the empirical formula of K2SO4?

Back

K2SO4

Front

How do you find the molecular formula from the empirical formula?

Back

Multiply the subscripts in the empirical formula by a whole number to match the molecular mass.

Front

What is the empirical formula for a compound with 40.05% sulfur and 59.95% oxygen?

Back

SO3

Front

What is the significance of the empirical formula in chemistry?

Back

It provides a basic understanding of the composition of a compound without detailing the structure.