# Question f6b8c

Aug 27, 2017

#### Answer:

$4.187 \cdot {10}^{25}$

#### Explanation:

For starters, you know that each molecule of carbon dioxide, ${\text{CO}}_{2}$, contains

• one atom of carbon, $1 \times \text{C}$
• two atoms of oxygen, $2 \times \text{O}$

This means that every mole of carbon dioxide will contain $2$ moles of oxygen atoms.

You can thus say that your sample will contain

34.77 color(red)(cancel(color(black)("moles CO"_2))) * "2 moles O"/(1color(red)(cancel(color(black)("mole CO"_2)))) = "69.54 moles O"

Now, in order to have $1$ mole of oxygen atoms, you need to have $6.022 \cdot {10}^{23}$ atoms of oxygen $\to$ this is given by Avogadro's constant.

This means that your sample will contain a total of

69.54 color(red)(cancel(color(black)("moles O"))) * (6.022 * 10^(23)color(white)(.)"atoms O")/(1color(red)(cancel(color(black)("mole O"))))#

$= \textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{4.187 \cdot {10}^{25} \textcolor{w h i t e}{.} \text{atoms O}}}}$

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