Actual & Theoretical Yield

  • Yield is the term used to describe the amount of product you get from a reaction.
  • In practice, you never get 100% yield in a chemical process for several reasons.
  • These include:
    • Some reactants may be left behind in the equipment.
    • The reaction may be reversible and in these reactions a high yield is never plausible as the products are continually turning back into the reactants.
    • Some product may also be lost during separation stages such as filtration or distillation.
    • There may be a side reaction occurring where a substance reacts with a gas in the air or an impurity in one of the reactants.
    • Products can also be lost during transfer from one container to another.
  • 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.
  • For economical reasons, the objective of every chemical producing company is to have as high a percentage yield as possible to increase profits and reduce costs and waste.

AQA GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.