Example 1 — Direct Percent Yield
Theoretical product = 8.00 g; actual isolated = 7.20 g.
Percent Yield Calculator
Percent Yield Calculator computes theoretical and actual yields, limiting reagent, efficiency percentage, step-by-step stoichiometry, with clear, LaTeX equations online.
Measured amount of product obtained from experiment.
Maximum possible amount predicted from stoichiometry (limiting reagent).
Equation Preview
%Yield = (Actual / Theoretical) × 100 =
(7.5 / 8.0) × 100 =
93.75%
Helping Notes
- Use consistent units (g, mol, mL); they cancel in the ratio.
- Theoretical yield comes from the balanced reaction and limiting reagent.
- Real reactions rarely reach 100% due to side reactions, losses, or incomplete conversion.
Results
Percent Yield
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Input Summary
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What Is a Percent Yield Calculator?
A Percent Yield Calculator helps chemists and students evaluate the efficiency of a chemical reaction. Laboratory reactions often experience losses due to side reactions, incomplete conversion, transfer, or purification steps. The calculator compares the actual yield obtained experimentally with the theoretical yield predicted from stoichiometry and the limiting reagent. It provides step-by-step guidance: identifying the limiting reagent, converting masses to moles, calculating theoretical product mass, and computing percent yield. Equation previews and unit checks ensure accuracy and ease of verification.
About the Percent Yield Calculator
Enter reactant identities (optional), molar masses, and starting amounts (mass or moles). Using the balanced chemical equation
the tool determines the limiting reagent by comparing available mole ratios to required stoichiometric ratios. The theoretical product moles follow from the limiting reagent, then multiplying by the product's molar mass gives the theoretical mass. Input the experimentally recovered product mass to compute percent yield. Optional outputs include percent error and overall yield for multistep syntheses. All formulas are displayed in LaTeX for reports or lab notebooks.How to Use the Percent Yield Calculator
- Enter the balanced chemical equation and molar masses (default values may be provided).
- Input starting amounts of each reactant (mass or moles); the calculator identifies the limiting reagent automatically.
- Review the theoretical yield of the target product (moles and grams) based on the limiting reagent.
- Enter the actual product mass recovered after workup and purification.
- Obtain percent yield, optional percent error, and overall yield for multistep reactions.
Core Formulas
Moles from mass:
Limiting reagent for }aA + bB \to cC\text{:}
Theoretical mass of product:
Percent yield:
Percent error (optional):
Overall multistep yield:
Examples
Example 2 — Limiting Reagent Controls Yield
Reaction: \( A + 2B \to C \), \( M_A = 50, M_B = 20, M_C = 90\,\text{g/mol} \).
Starting amounts: \( m_A = 10\,\text{g} \Rightarrow n_A = 0.20\,\text{mol} \), \( m_B = 12\,\text{g} \Rightarrow n_B = 0.60\,\text{mol} \).
Required B = 0.40 mol (available 0.60), so A is limiting.
\[ n_{C,\text{theor}} = 0.20\,\text{mol} \Rightarrow m_{C,\text{theor}} = 18.0\,\text{g} \]
If \( m_{C,\text{actual}} = 15.3\,\text{g} \), then
\[ \%\text{Yield} = \frac{15.3}{18.0} \times 100\% = 85\% \]
Example 3 — Overall Multistep Yield
Step yields: 80%, 75%, 90%
\[ \%\text{Overall} = 0.80 \times 0.75 \times 0.90 \times 100\% = 54\% \]
FAQs
What is percent yield?
It is the ratio of actual product obtained to the theoretical maximum, expressed as a percentage.
Why can percent yield be below 100%?
Losses occur due to side reactions, incomplete conversion, transfer, purification, or product instability.
Can percent yield exceed 100%?
Apparent yields above 100% usually result from impurities or residual solvent; purification reduces it.
Do I need a balanced equation?
Yes. Correct stoichiometric coefficients are essential to identify the limiting reagent and compute theoretical yield.
How do I handle hydrates or solvates?
Include the correct molar mass (including bound water or solvent) or convert consistently to anhydrous mass.
What if I start with volumes instead of masses?
Convert volumes to moles using \( n = C \times V \) with consistent units before applying stoichiometry.
How many significant figures should I report?
Report according to the least precise measurement, typically 2–3 significant figures in introductory labs.
How does reactant purity affect yield?
Impure reactants reduce effective moles. Adjust \( n \) by the purity fraction to avoid overestimating theoretical yield.
What is the difference between percent yield and atom economy?
Percent yield measures the efficiency of isolation, while atom economy measures theoretical resource utilization in reaction design.
How do I compute overall yield across steps?
Multiply step yields as fractions and convert to a percentage:
Does excess reagent increase percent yield?
It can push conversion toward completion but cannot exceed the theoretical maximum set by the limiting reagent.
Why does recrystallization reduce yield?
Product may remain dissolved or be lost during transfer/filtration; optimized technique and solvent choice minimize losses.