Question

a student balanced the chemical equation for the reaction of magnesium with oxygen by writing Mg + O2 ----> MgO2. What is wrong with this equation?

Answer 1

Step-by-step explanation:

Magnesium when it oxidizes has a valence of 2.

Oxygen, when it mixes with something, has a valence of - 2

So Mg and O2 will form something, but what? The answer is MgO

Mg + O2 ===> MgO

To balance this equation, you need 2 Magnesiums on the right and 2 Oxygens also on the right. The left will need a two Magnesiums.

The balanced equation will be

2Mg + O2 ====> 2MgO