Molecular and Empirical Formulas

Front

What is a molecular formula?

Back

A molecular formula shows the actual number and kinds of atoms present in one molecule of a compound.

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of the elements in 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 ratio of moles of each element.

Front

What is the relationship between empirical and molecular formulas?

Back

The molecular formula is a multiple of the empirical formula, indicating the actual number of atoms in a molecule.

Front

Given the empirical formula CH2O, what is the molecular formula if the molar mass is 120 g/mol?

Back

C4H8O4 (molecular formula is four times the empirical formula).

Front

What is the empirical formula for a compound with 63.50% silver, 8.25% nitrogen, and the remainder oxygen?

Back

AgNO3.

Front

If a compound consists of 72.2% magnesium and 27.8% nitrogen by mass, what is the empirical formula?

Back

Mg3N2.

Front

What is the empirical formula of a compound with a molecular formula of C6H12?

Back

CH2.

Front

How do you convert a molecular formula to an empirical formula?

Back

Divide the subscripts in the molecular formula by their greatest common divisor.

Front

What is the empirical formula for a compound with the molecular formula K8S4O16?

Back

K2SO4.