# Question e980d

Dec 2, 2016

$7.54 \cdot {10}^{- 15} \text{moles}$

#### Explanation:

The relationship between number of moles and number of molecules is given by Avogadro's constant, which essentially acts as the definition of the mole

$\textcolor{b l u e}{\underline{\textcolor{b l a c k}{\text{1 mole" = 6.022 * 10^(23)"molecules}}}}$

So, you know that you need to have exactly $6.022 \cdot {10}^{23}$ molecules of carbon dioxide in order to have $1$ mole of this molecular compound.

The problem provides you with a sample of

$454 , 000 , 000 = 4.54 \cdot {10}^{8}$

molecules of carbon dioxide, so use Avogadro's constant as a conversion factor to convert the number of molecules to number of moles

4.54 * 10^9 color(red)(cancel(color(black)("molecules CO"_2))) * "1 mole CO"_2/(6.022 * 10^(23)color(red)(cancel(color(black)("molecules CO"_2))))#

$= \textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{7.54 \cdot {10}^{- 15} {\text{moles CO}}_{2}}}}$

The answer is rounded to three sig figs, the number of sig figs you have for the number of molecules of carbon dioxide.