January 25th

Balancing Equations

Why do we balance equations?

We balance equations because of the Law of the Conservation of Matter which states that

MATTER CANNOT BE CREATED OR DESTROYED IN A CHEMICAL REACTION

This means that, for example, if you have 5 atoms of iron to begin with as a reactant, you will have 5 atoms of iron in the end product. That's why we need to balance our equations!

Balance THIS!

__ Cl₂ + __ LiI à __ LiCl + __ I₂

TIP: Balance the single elements last, as they are the easiest ones to work with (you want to balance the hard stuff first!) However, it might be easier in this case to look at the elements that exist naturally with a 2 subscript (the "Diatomic 7" - Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodine) and work with them.

__ Cl₂ + 2 LiI à 2 LiCl + __ I₂

Now balance the single elements.

1 Cl₂ + 2 LiI à 2 LiCl + 1 I₂ 

Remember, even if there's only one of an element, you still put the "1" in front when you're balancing.

Balance THIS!

__ FeBr₃ + __ (NH₄)₂ S à __ Fe₂S₃ + __ NH₄Br

TIP: Balance bigger "chunks" whenever you are able. The NH₄ above, for example, can be seen as one whole instead of as so-and-so many N's and H's (makes for less of a hassle).

__ FeBr₃ + 3 (NH₄)₂ S à __ Fe₂S₃ + 6 NH₄Br (we use 3 and 6 because we have already been given 3 Br's on the reactant side)

2 FeBr₃ + 3 (NH₄)₂ S à __ Fe₂S₃ + 6 NH₄Br

2 FeBr₃ + 3 (NH₄)₂ S à 1 Fe₂S₃ + 6 NH₄Br

THE BALANCING GAME

CLICK HERE for a fun game to practice balancing equations!

Maybe one day your balancing skills will be as good as his! Hehe...