Textbook problem H13

[805777063]

Hi all,

Can someone explain why the answer is O2 + N2 --> 2NO? I had just written O + N --> NO. Is it to be assumed that any atom in a gas phase has the subscript 2? Is this relevant to all atoms?

Thank you

[805777063]

to clarify ^ the question did not use the words diatomic or "dioxide gas" to know that there would be 2 of them

[506047744]

Whenever you use oxygen and nitrogen by themselves in balanced equations you use the subscript 2 as they are diatomic molecules: they always exist as 2 atoms. The other diatomic molecules include F, H, I, Cl and Br.

[105561735]

To add on to the point above, the molecule that does not exist as a diatomic molecule is Argon due to the fact that it is stable and chemically unreactive. This was one of the questions in the midterm so i thought it would be best if i add the point to the list