The composition of a binary material $($having elements $1$ and $2)$ can be expressed by using "weight percent" or "atomic percent". Derive the formula for converting weight percent to atom percent. What is the composition, in atom percent, of an alloy that consists of $30$ wt$\%$ Zn and $70$ wt$\%$ Ca$?$ Here, atomic weight of Zn $=65\mathrm{.}41$ g$/$mol and atomic weight of Ca $=63\mathrm{.}55$ g$/$mol$.$