Question

Why is NO3 called nitrate, but also called nitrogen trioxide? When is the proper time to use each of them?

Answer 1

a)

Note that

NO3 is always nitrogen trioxide GAS

NO3(g); this implies it is a neutral molecule, in gas phase

that is, Nitrogen will bond to 3 oxygen atoms so we must state that in the name, i.e. "trioxide" states three oxygens

Note that in real life, NO3(g) will decompose rapidly; therefore, when you hear Nitrates, it is most likely the ionic state:

NO3-(aq)

note that NO3- is -1 charged

this is mainly because

N = +5; O = -2

then,

N + 3O = -1

+5 + 3(-2) = -1

+5 = +5 as expected

that is,

NO3- i sonly found as ion

most likely in aqueous solution only

NO3-(aq)

therefore

only used NO3- when we talk about aqueous/water solutions

and NO3(g) whjen we talk about gases