$2C_2{H}_6(g)+7O_2(g)4C{O}_2(g)+6H_{2}O(g)H=-2855k\frac{J}{m}o{l}_{rxn}$

In a certain experiment, $125g{C}_2{H}_6(g)$ and $375g{O}_2(g)$ were added to a previously evacuated

reaction vessel. The reaction mixture was sparked and the reaction represented by the equation

shown above occurred until one of the reactants was completely consumed.

$($a$)$ Convert each quantity of reactant into mol ${?}_{rxn}.$