Question

How many moles of lead are in `1.50 * 10^12` atoms of lead?

Answer 1

`2.49 * 10^(-12)"moles Pb"`

Explanation:

Before doing any calculations, it's worth noting that atoms do not contain moles, it's the other way around.

A mole is simply a collection of atoms. More specifically, you need to have exactly `6.022 * 10^(23)` atoms of an element in order to have one mole of that element - this is known as Avogadro's number.

In your case, you must determine how many moles of lead would contain `1.50 * 10^(12)` atoms of lead.

Well, if you know that one mole of lead must contain `6.022 * 10^(23)` atoms of lead, it follows that you get `1.50 * 10^12` atoms of lead in

`1.50 * 10^12 color(red)(cancel(color(black)("atoms of Pb"))) * "1 mole Pb"/(6.022 * 10^(23)color(red)(cancel(color(black)("atoms of Pb")))) = color(green)(2.49 * 10^(-12)"moles Pb")`

Here's an excellent video on Avogadro's number and the mole featuring Professor Martyn Poliakoff from Periodic Videos