[poodlefish]

Dont fully understand how you balance equations...

I understand how you use numbers to make it equal on both sides, but I dont understand how the valence works....

For example, I'll do

Aluminium plus Oxygen goes into Aluminium Oxide

Al(val +3) + O2(val-2) > Al2O3

To balance it, I know you make it

4Al(val +3) + 3O2(val-2) > 2Al2O3

BUt i dont see how the valence comes into the picture, and how it works..

All help is greatly appreciated.

[Donaldson Tan]

the valency tells u how to determine the molecular formula of the product. then u vary the coefficients to get the equal number of atoms of each element on the LHS & RHS