# How do you convert 5.3 * 10^25 molecules of CO_2 to moles?

Jun 23, 2016

There are 88 moles of $C {O}_{2}$ in $5.3 \times {10}^{25}$ molecules of $C {O}_{2}$

#### Explanation:

In order to go from molecules of $C {O}_{2}$ to moles of $C {O}_{2}$, we have to use the following relationship:

I usually set up dimensional analysis questions like this:

Quantity sought = Quantity given x conversion factor

• Quantity sought $\rightarrow$ mol $C {O}_{2}$
• Quantity given $\rightarrow$ $5.3 \times {10}^{25}$ molecules
• Conversion factor $\rightarrow$ $\frac{1 m o l}{6.02 \times {10}^{23}}$

Now we just plug the values into the format I have above (make sure your units cancel out as you are going through this process, that's how you know if you are doing the calculations correctly or not):

moles $C {O}_{2}$ = $5.3 \times {10}^{25} \cancel{\text{molecules}} \times$(1mol)/(6.02xx10^(23)cancel"molecules"

moles $C {O}_{2}$ = 88 mol