Answer
a) $2CH_{4}+S_{8}\rightarrow 2CS_{2}+4H_{2}S$
b) $0.936\,mol$
Work Step by Step
a) The balanced chemical equation is
$2CH_{4}+S_{8}\rightarrow 2CS_{2}+4H_{2}S$
b) Calculating how much $CS_{2}$ can be made based on the amount of each reactant, we have
$120.\,g\times\frac{1\,mol\,CH_{4}}{16.04\,g}\times\frac{2\,mol\,CS_{2}}{2\,mol\,CH_{4}}=7.48\,mol\,CS_{2}$
$120.\,g\times\frac{1\,mol\,S_{8}}{256.48\,g}\times\frac{2\,mol\,CS_{2}}{1\,mol\,S_{8}}=0.936\,mol\,CS_{2}$
Since sulfur makes the least amount of $CS_{2}$, it is the limiting reactant. Theoretical yield is the maximum amount of product that can be made in a reaction based on the amount of limiting reactant. Therefore,
Theoretical yield=$0.936\,mol$
