Turn on thread page Beta
 You are Here: Home

# Balancing chemical equations watch

1. I have an exam this Friday and I have no idea how to balance chemical equations. I've watched so many videos on it and even in class, my teacher only went over it once. Can someone help me out on balancing chemical equations? THNX
Posted on the TSR App. Download from Apple or Google Play
2. The number of each atom needs to be the same on both sides of the equation. The ONLY thing you can do is change the coefficients of each species.

That's really all there is to it.

As an example:
C4H10 + O2 -> CO2 + H2O

As you can see, there is 4 C on the left but only 1 on the right. 10 H on the left but only 2 on the right. 2 O on the left but 3 on the right. Not balanced.

First balance C
C4H10 + O2 -> 4 CO2 + H2O

Then H
C4H10 + O2 -> 4 CO2 + 5 H2O

Finally need to do O and it gets a bit tricky. We have 8 O in the 4 CO2 and 5 O in the 5 H2O. 8 + 5 = 13 so we need to get 13 O atoms on the left. Since it is O2 if we do 13/2 (or 6.5) O2 then it will balance.

C4H10 + 13/2 O2 -> 4 CO2 + 5 H2O

But we don't really like seeing that fraction, so instead if we multiply the entire equation by 2 it will get rid of it.

2 C4H10 + 13 O2 -> 8 CO2 + 10 H2O
3. I would only add that there is a golden rule, one I have come to realise isn't obvious to all students:

Before you balance the sides of the equation you must make sure each formula you are using is the correct formula. Don't try to manipulate formulae for convenience - the formula is the formula regardless of how easy it makes balancing the equation.
It sounds obvious, but I have come across so many students who try to change formulae to make the balancing easier.

You may also want to have a look at my post here

Good luck with your test.

Turn on thread page Beta

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 11, 2017
Today on TSR

### Summer Bucket List is Back!

Start yours and you could win £150!

### GCSE Physics Equations sheet!

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE