Question

How many `N` atoms are there in one mole of `N_2`?

Answer 1

`2 xx N_"A"`

Explanation:

You know that one molecule of nitrogen gas, `"N"_color(blue)(2)`, contains two atoms of nitrogen, `color(blue)(2) xx "N"`.

Now, a mole is simply a very, very large collection of particles. In order to have one mole of things, let's say particles, you need to have `6.022 * 10^(23)` particles `->` this is known as Avogadro's constant and acts as the definition of the mole.

So, in one mole of nitrogen gas you have `6.022 * 10^(23)` molecules of nitrogen gas, `"N"_2`. But since each individual molecule consists of `2` atoms of nitrogen, the number of moles of nitrogen atoms will be twice that of nitrogen gas molecules.

`6.022 * 10^(23)color(red)(cancel(color(black)("molecules N"_2))) * (color(blue)(2)color(white)(a)"atoms of N")/(1color(red)(cancel(color(black)("molecule N"_2))))`

`= 1.2044 * 10^(24)"taoms of N"`

Alternatively, you can express this as `color(blue)(2) xx N_"A"`, where `N_"A"` is Avogadro's constant..