Theoretical Yield Calculator
Figure out the maximum amount of product a chemical reaction can produce. Enter the mass of your limiting reagent, both molar masses, and the balanced equation coefficients to get the theoretical yield in grams.
Theoretical yield is the maximum mass of product you can get from a reaction, assuming every molecule of the limiting reagent converts perfectly into product. Real reactions rarely hit this number because of side reactions, incomplete conversions, and transfer losses, but it sets the upper bound.
The Three-Step Process
- Convert the reactant mass to moles: divide grams by molar mass
- Apply the mole ratio from the balanced equation
- Convert product moles back to grams
Worked Example
Suppose you react 10 g of NaOH (molar mass 40 g/mol) with excess HCl. The balanced equation is NaOH + HCl -> NaCl + H2O, so the mole ratio is 1:1.
- Moles of NaOH = 10 / 40 = 0.25 mol
- Moles of NaCl = 0.25 mol (1:1 ratio)
- Theoretical yield = 0.25 x 58.44 = 14.61 g of NaCl
If the ratio were 2:1 (two moles of reactant per mole of product), you would halve the product moles before converting to grams.
Why It Matters
You need the theoretical yield to calculate percent yield, which tells you how efficient your reaction actually was. A percent yield of 85% on a 14.61 g theoretical yield means you collected about 12.42 g of product.