Answer
(a) $2\,mol\,A$
(b) $1.8\,mol\,A$
(c) $4\,mol\,B$
(d) $40\,mol\,B$
Work Step by Step
(a) Calculating how much product can be made based on the amount of each reactant, we have
$2\,mol\,A\times\frac{3\,mol\,C}{2\,mol\,A}=3\,mol\,C$
$5\,mol\,B\times\frac{3\,mol\,C}{4\,mol\,B}=3.75\,mol\,C$
Since $2\,mol\,A$ makes the least amount of product, it is the limiting reactant.
(b) Calculating how much product can be made based on the amount of each reactant, we have
$1.8\,mol\,A\times\frac{3\,mol\,C}{2\,mol\,A}=2.7\,mol\,C$
$4\,mol\,B\times\frac{3\,mol\,C}{4\,mol\,B}=3\,mol\,C$
Since $1.8\,mol\,A$ makes the least amount of product, it is the limiting reactant.
(c) Calculating how much product can be made based on the amount of each reactant, we have
$3\,mol\,A\times\frac{3\,mol\,C}{2\,mol\,A}=4.5\,mol\,C$
$4\,mol\,B\times\frac{3\,mol\,C}{4\,mol\,B}=3\,mol\,C$
Since $4\,mol\,B$ makes the least amount of product, it is the limiting reactant.
(d) Calculating how much product can be made based on the amount of each reactant, we have
$22\,mol\,A\times\frac{3\,mol\,C}{2\,mol\,A}=33\,mol\,C$
$40\,mol\,B\times\frac{3\,mol\,C}{4\,mol\,B}=30\,mol\,C$
Since $40\,mol\,B$ makes the least amount of product, it is the limiting reactant.
