Percent Yield
Also known as actual over theoretical
Worked example: 4.10 g isolated of 5.00 g theoretical → 82% yield — press Try an example to run it live, then adjust anything.
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Paper versus flask →
Grade 11Grade 11 Chemistry
Yield on the batch record →
UniversityProcess & Water Chemistry
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Percent Yield explained
A balanced equation promises a certain mass of product; the flask rarely delivers all of it. Side reactions consume reactant, some product stays dissolved in the mother liquor, and a little is always lost on filter paper and glassware. Percent yield is the honest scorecard: the mass you actually isolated divided by the stoichiometric maximum, times 100. In a classic teaching lab, synthesizing aspirin from salicylic acid might predict 5.00 g of product; if 4.21 g of dry crystals come off the funnel, the yield is 84.2%.
The number matters far beyond the classroom. Process chemists judge manufacturing routes largely by yield, because in a multi-step synthesis losses multiply — five steps at 80% each deliver only 33% overall. A reported yield above 100% is a red flag, not a triumph: it usually means the product is still wet or carries impurities.
Percent Yield formula
- = Percent yield (%)
- = Actual yield (mass obtained) (kg)
- = Theoretical yield (mass predicted) (kg)
Missing one of these? Work it out first, then come back
- Percent yield — Mass Percent of a Solution, Percent Ionization of a Weak Acid
- Actual yield (mass obtained) — Density, Sensible Heat (Q = mcΔT)
- Theoretical yield (mass predicted) — Density, Sensible Heat (Q = mcΔT)