# How can I calculate the empirical formula of magnesium oxide?

##### 1 Answer

You need to do an experiment to determine how much

#### Explanation:

For example, you might heat a known mass of magnesium in a crucible and determine the mass of oxide formed.

**EXAMPLE**

Assume that you heated 0.297 g of magnesium and obtained 0.493 g of the oxide. What is the empirical formula of magnesium oxide?

**Solution**

The empirical formula is the simplest whole-number ratio of atoms in a compound.

The ratio of atoms is the same as the ratio of moles. So our job is to calculate the molar ratio of

To get this into an integer ratio, we divide both numerator and denominator by the smaller value.

From this point on, I like to summarize the calculations in a table.

There is 1 mol of

The empirical formula of magnesium oxide is

Here is a video that illustrates how to determine an empirical formula.