How do you calculate the percent yield of copper?
You divide the actual yield by the theoretical yield and multiply by 100.
EXAMPLE
What is the if 0.650 g of copper are formed when excess aluminum reacts with a 2.00 g of copper(II) chloride dihydrate according to the equation
Step 1. Write the balanced chemical equation
3CuCl₂·2H₂O + 2Al → 3Cu + 2AlCl₃ + 2H₂O
Step 2. Calculate the theoretical yield of Cu
(a) Calculate the moles of 3CuCl₂·2H₂O
##”2.00 g CuCl”_2·2″H”_2″O” × (“1 mol CuCl“_2·2″H”_2″O”)/(“170.5 g CuCl”_2·2″H”_2″O”) = “0.011 73 mol CuCl”_2·2″H”_2″O”##
(b) Calculate the moles of Cu
##”0.011 73 mol CuCl”_2·2″H”_2″O” × “3 mol Cu”/(“3 mol CuCl”_2·2″H”_2″O”) = “0.011 73 mol Cu”##
(c) Calculate the theoretical yield
##”0.011 73 mol Cu”× “63.55 g Cu”/”1 mol Cu” = “0.7455 g Cu”##
Step 3. Calculate the percent yield.
% yield = ##”theoretical yield”/”actual yield” × 100 % = “0.650 g”/”0.7455 g” × 100 %## = 87.2 %