Help please

[Modyasoo1]

thanks and can you tell me

Why it's one mole of nitrogen atoms why it's not one mole of nitrogen molecules or ions?


And something more..

How i know if 1=2 and 1.5=3 in the empirical formula because sometimes 1=1 like CH2

Here Carbon is 1

And here C2H3

Carbon is 1 too
and Hydrogen is 1.5

how to know that please and thanks