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

Nov 24, 2015

$2.49 \cdot {10}^{- 12} \text{moles Pb}$

#### 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 $6.022 \cdot {10}^{23}$ 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 $1.50 \cdot {10}^{12}$ atoms of lead.

Well, if you know that one mole of lead must contain $6.022 \cdot {10}^{23}$ atoms of lead, it follows that you get $1.50 \cdot {10}^{12}$ 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