Last class we learnt how to balance equations. You probably remember doing this last year and if you don't, then no worries. That's why we have this blog :). Plus it's one of the easiest things to learn in chemistry. Ok time for review/notes.
The reason why we balance is not just to add extra work but it's to make sure the number of atoms on the reactant side is the same as the number of atoms as the product. Here are a few tips to help you out.
- First balance the atoms that only appear once on each side of the equation.
- Make sure to balance polyatomic ions as one group.
- Balance atoms and groups as you go, don't skip around.
- Balance atoms in elemental form last because those are super easy to balance.
Time to practice balancing equations.
Here's a simple example to get the idea of it.
H
2 + O
2 -> H
2O
-Remember to put a subscript 2 next to diatomic elements. (e.g H2 + O2)
Ok so in the equation you see 2 hydrogen and 2 oxygen as the reactants.
On the product side you see 2 hydrogen and only 1 oxygen.
How would you balance it out to make the amount of atoms equal?
Multiply the product to make the oxygen atoms the same as the reactants.
H
2 + O
2 ->
2H
2O
Now we have 4 hydrogen and 2 oxygen on the product side.
Since there's already 2 oxygen on the reactants side, you don't need to balance it but you must put a 1 in front to indicate that it's already balanced.
To make the hydrogen equal, just multiply it by 2 as well.
2H
2 +
1O
2 ->
2H
2O
Now the equation is balance, both sides have an equal amount of atoms. You can check by counting.
That's about all there is to it. If you need further explanation here's a youtube video getting into more detail about balancing equations. http://www.youtube.com/watch?v=RnGu3xO2h74
Here are some practice questions and answers. http://misterguch.brinkster.net/PRA008.pdf
Thanks for reading :) Hope you understand how to balance equations now.
