Question

Calculate the theoretical yield of C2H5Cl when 117 g of C2H6 reacts with 239 g of Cl2, assuming that C2H6 and Cl2 react only to form C2H5Cl and HCl.

Answer 1

C2H6 + Cl2 --> C2H5Cl + HCl
Calculate the moles of C2H6 available-
117 g / 30 g/mol = 3.9 mol C2H6
Calculate moles of Cl2 available-
239 g / 71 g/mol = 3.37 mole
Note that Cl2 is the limiting reactant; 3.9 mol C2H6 would require 3.9 mol of Cl2, but only 3.37 mol of Cl2 is available.
3.37 mol Cl2 at 100% yield would yield 3.37 mol C2H5Cl.
Calculate the mass of C2H5Cl formed at 100% yield-
3.37 mol x 64.5 g/mol = 217.365 g of C2H5Cl

Calculate the percent yield of C2H5Cl actually formed-
180 g / 200 g = 90%