How to balance a chemical equation.

Balancing chemical equations can seem tricky at first, especially when starting out. But by following an order it becomes a quick and easy task.

For the sake of this question, we'll balance this equation:
C₅H₁₂ + O₂ → CO₂ + H₂O

It's easiest to start from left to right and work your way along until the equation is balanced, then any cancellation can be done.

1. C₅H₁₂ + O₂ → CO₂ + H₂O
We can see there are 5 carbons on the left and only 1 on the right, so balance the carbons first.

2. C₅H₁₂ + O₂ → 5CO₂ + H₂O2. C₅H₁₂ + O₂ → 5CO₂ + H₂O
There are 12 hydrogens on the left but only 2 on the right, so multiply by 6 to balance.

3. C₅H₁₂ + O₂ → 5CO₂ + 6H₂O3. C₅H₁₂ + O₂ → 5CO₂ + 6H₂O
Now the right hand side has much more oxygens than the left, 10 from the 5CO₂ and 6 from the 6H₂O for a total of 16.

So, multiply the O₂ on the left by 8 to get:

16.C₅H₁₂ + 8O₂ → 5CO₂ + H₂O

And there you go, the equation is balanced. Working systematically works for even complicated equations.