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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: poodlefish on February 14, 2005, 03:54:23 AM

Title: Dont fully understand how you balance equations
Post by: poodlefish on February 14, 2005, 03:54:23 AM

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.

Title: Re:Dont fully understand how you balance equations
Post by: Donaldson Tan on February 14, 2005, 09:25:26 AM

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