Theoretical Yield Calculator

Theoretical Yield Calculator

What is Theoretical Yield?

Theoretical Yield is a fundamental concept in chemistry that represents the maximum possible amount of a product that can be formed in a chemical reaction. It is an "on-paper" calculation based on the stoichiometry of a balanced chemical equation and assumes a perfect reaction where 100% of the starting materials (reactants) are converted to products with no losses.

This value is a crucial baseline for chemists. By comparing the actual yield (the amount of product physically obtained in a lab) to the theoretical yield, one can determine the reaction's percent yield, which measures its efficiency.

Frequently Asked Questions

Why is my actual yield almost always less than the theoretical yield?

It's very rare for a reaction to be 100% efficient. Several factors can lead to a lower actual yield:
Incomplete Reaction: The reaction may not have run for long enough or at the correct conditions to fully complete.
Side Reactions: The reactants may have formed other, undesired products (byproducts).
Loss of Product: Product is often lost during the purification and collection process (e.g., sticking to glassware, remaining dissolved in a solvent, or being spilled).
Equilibrium: Many reactions are reversible, meaning they reach a point where products are turning back into reactants, so they never reach 100% completion.

What's the difference between limiting reagent and theoretical yield?

They are related but different concepts:
• The Limiting Reagent is the reactant that will be completely used up first, causing the reaction to stop.
• The Theoretical Yield is the product mass that you calculate based on the starting amount of that limiting reagent.
In short, the limiting reagent determines the theoretical yield.

What if my actual yield is *more* than my theoretical yield?

A percent yield over 100% is physically impossible and indicates an error. The most common cause is that the product you weighed is impure. For example, it might still be wet with a solvent (like water), or it could be contaminated with a leftover reactant or a byproduct, all of which add to its measured mass.