Question #7792a

1 Answer
Nathan L.
Jun 21, 2017

I'll try and interpret the question correctly...

Explanation:

The first question is why nitrogen dioxide is NO2 (I believe).

This comes from the nomenclature of nonmetal compounds; for binary covalent compounds such as nitrogen dioxide, they are named such that prefixes are attached to each element ( except if the first element has only 1 of it in the compound, then no prefix is present).

"Nitrogen dioxide" thus means there is one nitrogen present and two oxygen atoms (prefix "di-" indicates 2), the compound formula is NO2.

The next question, I assume, is why the formula is not something else according to the chemical reaction

N2(g)+O2(g)→NO2(g) (unbalanced)

Here's something worth knowing about chemistry and specifically chemical reactions: reactants can form products that have completely different characteristics than those of the reactants.

The fact that N2 seems to lose its diatomic property is just the nature of the reaction; although N2O2 is a real compound, it is far less common to hear about it or work with it.

Basically, the chemical structure of NO2 is thermodynamically more favorable than that of N2O2, and thus the reaction will, under certain conditions, yield NO2 (you'll learn more about the thermodynamics of reactions later!)

As far as balancing goes, we have so far

  • two nitrogens on the left, one on the right

  • two oxygens on the left, two on the right

Therefore, nitrogen is the only unbalanced element. To fix this, we simply add a 2 in front of NO2:

N2(g)+O2(g)→2NO2(g) (unbalanced)

Now you may notice that the oxygen quantities have become unbalanced, and there are 4 on the right side and 2 on the left. A quick fix is done by placing another 2 in front of O2:

N2(g)+2O2(g)→2NO2(g) (balanced)

And our equation is balanced!

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