Theoretical yield — Science definition
The maximum amount of product predicted by stoichiometry, assuming the reaction goes perfectly and the limiting reactant is fully converted.
Where it is taught
- Limiting Reactants & Percent Yield — Stoichiometry & Yield, Physical Science: Chemistry, Grade 11
In use
Stoichiometry gives you the theoretical yield: the maximum product possible if every bit of the limiting reactant converts perfectly and nothing is lost.
Limiting Reactants & Percent Yield
Questions using theoretical yield
Problem 1
A reaction has a theoretical yield of 50.0 g but an actual yield of 45.0 g. What is the percent yield?
Answer and explanation
90 %
percent yield = (45.0 ÷ 50.0) × 100% = 90%.
Problem 2
A student predicts a theoretical yield of 25.0 g but isolates only 20.0 g of product. What is the percent yield?
Answer and explanation
80 %
percent yield = (20.0 ÷ 25.0) × 100% = 80%.
Problem 3
A reaction has a theoretical yield of 8.00 g. If it runs at 75.0% yield, what is the actual yield?
Answer and explanation
6 g
actual yield = percent yield × theoretical yield = 0.750 × 8.00 g = 6.00 g.
Problem 4
Theoretical yield is 25 g and actual isolated yield is 20 g. Find percent yield. Show the reasoning, not just the conclusion.
Hints
Compare required ratios, not just smaller starting mole count.
Answer and explanation
20/25×100%=80%.