How do you balance and unbalanced equation in chemistry?

Balancing an equation in chemistry implies that the amount(moles) of one atom is the same as the other side, like in algebra. The tricky part is when trying to balance equation you can only change the amount(moles) of each compound(group of atoms that form a molecule). A good trick is to start with the largest molecule then work to the smaller ones (like ions, diatomic particles and water). If you would like to check your answer use: http://www.webqc.org/balance.php

ex:.

KMnO4 + HCl = KCl + MnCl2 + H2O + Cl2

balanced: 2 KMnO4 + 16 HCl = 2 KCl + 2 MnCl2 + 8 H2O + 5 Cl2

to check count the individual atoms on each side:

2 Potassium

2 Manganese

8 Oxygene

16 Hydrogen

16 Chlorine