J.R. S. answered 01/07/21
Ph.D. University Professor with 10+ years Tutoring Experience
First, write the correctly balanced equation for the reaction:
2C2H2 + 5O2 ==> 4CO2 + 2H2O ... balanced equation for combustion of acetylene
Since we are given moles of BOTH reactants, we must first find which reactant is limiting.
Simply divide moles of each by their respective coefficient to see which is limiting:
--- 13.0 mol C2H2 / 2 = 6.5
--- 11.0 mol O2 / 5 = 2.2
Since 2.2 is < 6.5, this tells us that 11.0 mol O2 is limiting and will run out first. It is the limiting reactant that determines how much product will form.
Largest amount of CO2 that can form = 11.0 mol O2 x 4 mol CO2 / 5 mol O2 = 8.8 moles CO2