- Yield is the term used to describe the amount of product you get from a reaction.
- The actual yield is the recorded amount of product obtained.
- The theoretical yield is the amount of product that would be obtained under perfect practical and chemical conditions.
- It is calculated from the balanced equation and reacting masses.
- The percentage yield compares the actual yield to the theoretical yield.
Percentage Yield = (actual yield ÷ theoretical yield) x 100
In an experiment to displace copper from copper sulfate, 6.5g of zinc was added to an excess of copper (II) sulfate solution. The copper was filtered off, washed and dried. The mass of copper obtained was 4.8g. Calculate the percentage yield of copper.
Equation of Reaction:
Zn (s) + CuSO4 (aq) → ZnSO4 (aq) + Cu (s)
Step 1 Calculate the Moles of Zinc Reacted
Moles of Zinc = 6.5 ÷ 65 = 0.10 moles
Step 2 Calculate the Maximum Amount of Copper that could be formed from the
Maximum Moles of Copper = 0.10 moles (Molar ratio is 1:1)
Step 3 Calculate the Maximum Mass of Copper that could be Formed
Maximum Mass of Copper = ( 0.10 x 63.5 ) = 6.35 g
Step 4 Calculate the Percentage Yield of Copper
Percentage Yield = ( 4.8 ÷ 6.35 ) x 100 = 75.6%
Percentage Yield of Copper = 75.6%