3.1.10

Percentage Yield

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Percentage Yield

The percentage yield for any reaction is always less than 100%. The following 4 factors make sure the percentage yield of reactions stays below 100%:

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Incomplete reactions

  • An incomplete reaction can happen because:
    • The reaction is very slow and hasn't been given enough time to happen.
    • The reaction is reversible and some of the products have been converted back into reactants.
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Waste

  • Some of the chemicals will remain stuck to the apparatus and will be wasted.
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Extraction

  • It might be difficult to fully separate the product from the reaction mixture.
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Side reactions

  • Unexpected reactions (side reactions) can happen. This may mean that the intended product is not created.

Calculating Percentage Yield

The percentage yield of a reaction is calculated as the real yield divided by the theoretical yield multiplied by 100.

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Real yield

  • The real yield is the mass of a desired product obtained from a reaction.
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Theoretical yield

  • The theoretical yield is the maximum mass of a product that could possibly be created from a reaction.
  • This can be calculated from a balanced equation if we know the mass of the reactants.
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Percentage yield

  • A comparison of the real and theoretical yields of a reaction.

Jump to other topics

1Atomic Structure

2Chemical Bonding

3Quantitative Chemistry

4Chemical Changes

5Energy Changes

6The Rate & Extent of Chemical Change

7Organic Chemistry

8Chemical Analysis

9Chemistry of the Atmosphere

10Using Resources

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