Rules for Balancing Equations

بسم الله الرحمن الرحيم

Assalamu Alaikum,

SPIDERMAN! This is for you. =)

1. Make sure the compounds are written correctly. Trying to balance an equation with incorrectly written compounds will most probably blow up your brain. For example: Na2NO3 does not exist. It is NaNO3.
2. If there is the same polyatomic cation/anion on both sides of the equation, it is must easier to count how many polyatomic ions there are on each side than each individual atoms in the polyatomic ion. For example, if PO4 (3-) appears on both sides (Na3PO4 and Mg3(PO4)2 ) rather than counting each Phosphorous atom and Oxygen atom, just count 1 PO4 (3-) on one side and 2 PO4(3-) on the other side.
3. Atoms in single elemental form: i.e. Ag (s), Ne (g), Zn (s). You will balance them last because you can easily change the coefficient without worrying something else will be affected.
4. Combustion reactions with hydrocarbons: you balance carbon, hydrogen and oxygen IN THAT ORDER. Saves you approximately five headaches. (Clouds Hovering Over is a way to remember it–Carbon, Hydrogen and Oxygen)
5. For oxidation reduction reactions: Yes, you must have the same number of moles of each atom on both sides, but you need to make sure the net charge on each side is equal: so if you have +6 on the reactant side, you must have +6 on the product side. Remember, it is the NET charge so you can have +8 and -2 on one side and +6 on the other.
6. Thou shalt not forget to double TRIPLE check your final balanced equation to make sure you didn’t miss anything.
7. If you somehow got a fraction when balancing, you can multiply each mole coefficient by the denominator so you can get rid of it on the original fraction.
8. If you exceed 30 moles as a mole coefficient, that is typically a sign you may have messed up or you did not simplify. It can happen, it would just be really strange….
9. If you are in a severe jam, put an 8 in front of one compound and try to balance it from there. If it is too big, you are welcome to reduce it.
10. If you see MnO4 (-) or Cr2O7 (2-) as a reactant, an oxidation reduction reaction occurred. Check your charges!

—

Okay, that should be good.