# How many moles are in 7.5*10^78 atoms of zinc?

Hmm $\left(7.5 \times {10}^{78} \text{ zinc atoms")/(6.022xx10^23" zinc atoms } m o {l}^{-} 1\right)$ $=$ ??? mol
So this approximately ${10}^{55}$ $\text{moles}$. Given that world production of zinc was approx $1 \times {10}^{9}$ $g$, in 2015, approx., ${10}^{7}$ moles, this amount probably represents more of the metal than exists on Earth, and possibly more than the entire amount of zinc present in the solar system. So this is not a serious question.