Question #19e89

1 Answer
Jan 16, 2014

You divide the actual yield by the theoretical yield and multiply by 100.

EXAMPLE

What is the percent yield 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 CuCl22H2O×1 mol CuCl22H2O170.5 g CuCl22H2O=0.011 73 mol CuCl22H2O

(b) Calculate the moles of Cu

0.011 73 mol CuCl22H2O×3 mol Cu3 mol CuCl22H2O=0.011 73 mol Cu

(c) Calculate the theoretical yield

0.011 73 mol Cu×63.55 g Cu1 mol Cu=0.7455 g Cu

Step 3. Calculate the percent yield.

% yield = theoretical yieldactual yield×100%=0.650 g0.7455 g×100% = 87.2 %