# How many moles are equal to 1.2 times 10^21 molecules of lithium?

Mar 19, 2017

$1.2 \times {10}^{21} \textcolor{w h i t e}{.} \text{atoms Li"=2.0xx10^(-3)color(white)(.)"mol Li}$.
Lithium is a metal. It does not exist as molecules. We can, however, determine the moles equal to $1.2 \times {10}^{21}$ atoms of lithium.
$\text{1 mol atoms} = 6.022 \times {10}^{23}$ atoms
1.2xx10^21color(red)cancel(color(black)("atoms Li"))xx(1"mol Li atoms")/(6.022xx10^23color(red)cancel(color(black)("atoms Li")))=2.0xx10^(-3)"mol Li" (rounded to two significant figures)