Empirical and Molecular Formulas

Front

What is an empirical formula?

Back

An empirical formula is 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 and kinds of atoms present in one molecule of a compound.

Front

How do you determine the number of Carbons in a molecular formula like C18H34O3?

Back

Count the number of 'C' in the formula; in C18H34O3, there are 18 Carbons.

Front

What is the empirical formula of C2F6?

Back

The empirical formula is CF3.

Front

How do you calculate the molar mass of a compound?

Back

Add the atomic masses of all atoms in the molecular formula.

Front

What is the molar mass of C4H6?

Back

The molar mass is calculated as 4(12.0111) + 6(1.00794).

Front

What does the subscript in a chemical formula represent?

Back

The subscript indicates the number of atoms of the element in the molecule.

Front

What is the difference between empirical and molecular formulas?

Back

Empirical formulas show the simplest ratio of elements, while molecular formulas show the actual number of atoms.

Front

How can you derive the empirical formula from the molecular formula?

Back

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

Front

What is the empirical formula of K2SO4?

Back

The empirical formula is K2SO4.