Balancing Equations: Nitrogen Dioxide + Water = Nitric Acid

[recon]

Hi,

I've always had trouble balancing equations. Does anyone know if there is an 'algorithm' for balancing equations? For example, how do I balance

"Nitrogen Dioxide + Water = Nitric Acid"-Sorry, don't know how to use Latex!

Any help will be greatly welcomed.

 

[ShawnD]

What I always do is balance things in this order:
1. complex ions
2. atoms with relatively low numbers
3. atoms with high numbers

Here is what you wanted balanced (I think)

NO_2 + H_2O \rightarrow HNO_3

This equation by itself cannot be balanced. The nitrogens balance, the oxygens balance, but the hydrogens do not balance. Trying to balance the hydrogens makes the problem bigger.

The reason it cannot be done is because that equation is not correct. The real reaction that happens is:
nitrogen dioxide + water + oxygen = nitric acid

NO_2 + H_2O + O_2 \rightarrow HNO_3 (unbalanced)

Here is balanced:

4NO_2 + 2H_2O + O_2 \rightarrow 4HNO_3

This is a strange reaction that my method doesn't work too well on. I started by balancing hydrogens, then nitrogens, then oxygen.