# If you are given 2.13 x10^24 atoms Au, how do you determine the moles in the sample and the mass of the sample?

Dec 4, 2016

Divide the given number by $\text{Avogadro's number}$, and then mulitply this number, the number of $\text{moles of gold}$ by the $\text{molar mass}$ of gold.

#### Explanation:

$\text{Moles of gold atom}$ $=$ $\left(2.13 \times {10}^{24} \text{ gold atoms")/(6.022xx10^23" gold atoms} \cdot m o {l}^{-} 1\right)$

$\cong$ $3.5 \cdot m o l$

And then we multiply this number by the molar mass of gold:

$3.5 \cdot m o l \times 197.0 \cdot g \cdot m o {l}^{-} 1$ $\cong$ $700 \cdot g$

Today's price of gold is \$38-00" USD "g^-1.

How much is your mass worth?