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Calculating percentage yield

Syllabus VWO: Quantities and relationships

Question 1 / 50 correct

29.0 g is weighed although at most 27.2 g of pure product is possible. What could explain this?

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More explanation and a worked example

A maximum and a measurement

The theoretical yield follows from the reaction ratio and limiting reactant. The actual yield is the amount of pure product obtained. Percentage yield = actual / theoretical × 100%.

More than 100% needs an explanation

A wet or impure product can give an excessive measured mass. This does not prove extra conversion. Percentage yield is also different from energy efficiency or atom economy.

Theoretically 1.60 mol NH₃ forms. M = 17.0 g/mol. You collect 20.4 g.

  1. Theoretical mass = 1.60 × 17.0 = 27.2 g.
  2. Percentage yield = 20.4 / 27.2 × 100%.
The yield is 75.0%.
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