How would you balance the following equation: Mg (s) + O2 (g) → MgO (s)?

By BYJU'S Exam Prep

Updated on: September 25th, 2023

The balanced equation of Mg (s) + O2 (g) → MgO (s) is 2Mg (s) + O2 (g) → 2MgO (s). When balancing chemical equations, we aim for an equal number of each type of atom on both sides. All that is altered are the coefficients. Coefficients are the numbers in front of the molecule. Subscripts ought never ever to be altered. Prior to balancing nonmetals, such as oxygen and hydrogen, metals must first be balanced.

Table of content

1. How would you balance the following equation: Mg (s) + O2 (g) → MgO (s)?

Balancing the Chemical Equation

The unbalanced chemical reaction provided is Mg (s) + O2 (g) → MgO (s)

Magnesium + Oxygen gas → Magnesium oxide

It involves both redox and combustion.

Reactant side:

1 Magnesium atom from Mg
2 Oxygen atoms from O2

Product side:

1 Magnesium atom from MgO
1 Oxygen atom from MgO

We must place two oxygen atoms on the right side before magnesium oxide because, as we can see, there are two oxygen atoms on the left.

Mg (s) + O2 (g) → 2MgO (s)

Magnesium + Oxygen gas → Magnesium oxide

Reactant side:

1 Magnesium atom from Mg
2 Oxygen atoms from O2

Product side:

2 Magnesium atoms from MgO
2 Oxygen atoms from MgO

Magnesium must be balanced at the end of the process. Since there is one Mg atom on the left and two Mg atoms on the product side, we must place a 2 before Magnesium on the reactant side, making the equation balanced.

Reactant side:

2 Magnesium atoms from Mg
2 Oxygen atoms from O2

Product side:

2 Magnesium atoms from MgO
2 Oxygen atoms from MgO

The balanced chemical reaction is as follows:

2Mg (s) + O2 (g) → 2MgO (s)

Magnesium + Oxygen gas → Magnesium oxide

Summary: