# How would you balance this chemical equation: C_3H_8 + O_2 -> 3CO_2 + 4H_2O?

May 23, 2017

${C}_{3} {H}_{8} + 5 {O}_{2} \rightarrow 3 C {O}_{2} + 4 {H}_{2} O$

#### Explanation:

Let's look for each element one by one to see which element(s) needs balancing.

Carbon is balanced : there are 3 carbon atoms on the LHS, and 3 carbons on the RHS.

Hydrogen is balanced : There are 8 hydrogen atoms on the LHS, and 4 of 2 hydrogen atoms on the RHS, making it 8 atoms in total.

Oxygen is not balanced : there are 2 oxygen atoms on the LHS, but 10 oxygens on the RHS.

How many times does 2 go into 10? The answer is 5

${C}_{3} {H}_{8} + 5 {O}_{2} \rightarrow 3 C {O}_{2} + 4 {H}_{2} O$

There are 6 carbon atoms, 16 hydrogen atoms and 14 oxygen atoms on each side of the equation. It is now balanced.