The theoretical yield is the maximum amount of product that can be formed in a chemical reaction, calculated from the balanced chemical equation and the amount of the limiting reactant.
It represents the ideal yield assuming the reaction goes perfectly, with no side reactions or losses. In real experiments, the actual yield is usually less than the theoretical yield because of factors like incomplete reactions, impurities, or practical handling losses.
Steps to determine theoretical yield:
- Balance the chemical equation.
- Identify the limiting reactant.
- Convert the amount of limiting reactant into moles (if needed).
- Use the mole ratio to find moles of product that can form.
- Convert moles of product into grams (if required).
Example:
Reaction: 2H₂ + O₂ → 2H₂O
If 4 moles of H₂ and 2 moles of O₂ are available:
- From the ratio, 2 moles H₂ produce 2 moles H₂O.
- 4 moles H₂ would produce 4 moles H₂O (theoretical yield).
In short, the theoretical yield is the calculated “best-case scenario” amount of product possible.