Chemistry help please?

When ethane, C2H6, reacts with chlorine, Cl2, the main product is C2H5Cl, but other products containing Cl such as C2H4Cl2 are also obtained in small quantities. The formation of these other products reduces the yield of C2H5Cl. Calculate the percent yield of C2H5Cl if the reaction of 125 g of C2H6 with 255 g of Cl2 produced 206 g of C2H5Cl.