How to balance a chemical equation.

  • Google+ icon
  • LinkedIn icon

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

C5H12 + O2 → 5CO2 + H2O

2. C5H12 + O2 → 5CO2 + H2O

There are 12 hydrogens on the left but only 2 on the right, so multiply by 6 to balance.

C5H12 + O2 → 5CO2 + 6H2O

3. C5H12 + O2 → 5CO2 + 6H2O

Now the right hand side has much more oxygens than the left, 10 from the 5COand 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.

Youssef M. GCSE Biology tutor, GCSE Chemistry tutor, GCSE Maths tutor

About the author

is an online GCSE Chemistry tutor with MyTutor studying at Birmingham University

Still stuck? Get one-to-one help from a personally interviewed subject specialist.

95% of our customers rate us

Browse tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss