What is the number of representative particles in 3.0 mol Sn?

Mar 13, 2016

There are $3 \times {N}_{A} \text{ tin atoms}$ in $3.0$ $m o l$ of tin metal, where ${N}_{A}$ is Avogadro's number, $6.022 \times {10}^{23}$ $m o {l}^{-} 1$.
If I simply wrote $3 \times {N}_{A}$, I think that would be an acceptable answer. Of course, you'll have to do the multiplication.
So why do we use the number ${N}_{A}$?
${N}_{A}$ has the property that ${N}_{A}$ ""^1H atoms have a mass of $1.00$ $g$. ${N}_{A}$ ""^12C atoms have a mass of $12.00$ $g$. And ${N}_{A}$ $S n$ atoms has a mass of $118.7$ $g$. What is the mass of your quantity?