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 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 does a subscript in a chemical formula indicate?

Back

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

Front

How do you calculate the molar mass of a compound?

Back

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

Front

What is the empirical formula for C4H6?

Back

The empirical formula is C2H3.

Front

If the empirical formula is CF2 and the molecular formula mass is 192 g/mol, what is the molecular formula?

Back

The molecular formula is C4F8.

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 do you find the empirical formula from a molecular formula?

Back

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

Front

What is the molar mass of C2H4?

Back

The molar mass is 28.05 g/mol (2*12.01 + 4*1.01).