Question

A sample of carbon dioxide gas (CO2) contains 8.551 x 1025 molecules. How many moles of carbon dioxide does this represent?

Answer 1

Answer:

142.0 moles CO₂

Explanation:

To answer this question, we first need to know what a mole is. A mole represents $6.022 \cdot 10^{23}$ of something, and in this case, that something is molecules.

So, to convert $8.551 \cdot 10^{25}$ molecules into moles, we need to use the conversion factor  $1=\frac{6.022\cdot 10^{23} \text{molecules} }{ \text{1 mole}}$.

Doing so (using dimensional analysis) gives us:

$8.551 \cdot 10^{25} \text{ molecules } \cdot \frac{\text{1 mole}}{ 6.022\cdot 10^{23} \text{ molecules} } = \frac{8.551 \cdot 10^{25}}{ 6.022\cdot 10^{23}} \text{ moles CO}_2 = \\ \\ 141.996 \text{ moles CO}_2 = \boxed{142.0 \text{ moles CO}_2 }$