A molecular
formula is the formula for a compound as it exists in nature.
For example: the molecular formula for hydrogen peroxide is H2O2.
These formulas should not be reduced.
A reduced version of a molecular formula is called the empirical formula.
How to Calculate a Molecular Formula from an Empirical Formula
Example: For a compound with an empirical formula C4H9 ,
determine its molecular formula if its molecular formula mass is 114.0
g/mol.
Description
of Action |
Action |
| 1. Determine
the gram formula mass of the empirical formula. |
C: 4 x 12.0 = 48.0
H: 9 x 1.0 = 9.0
48.0 + 9.0 = 57.0 g/mol |
| 2. Divide the molecular formula mass by the empirical
formula mass. |
114.0 ÷ 57.0
= 2 |
| 3. Multiply
each subscript in your empirical formula by your result. |
C4H9 becomes C8H18 |
|
|
