Stoichiometry Mass-to-Mass Calculator
Convert a known mass of one species in a balanced reaction into the mass of another using molar masses and the mole ratio.
g
g/mol
g/mol
Predicted mass produced from the given reactant
- 1
Moles of reactant A
10 g ÷ 18.015 g/mol = 0.5551 - 2
Mole ratio (coeff B ÷ coeff A)
1 ÷ 2 = 0.5Taken directly from the balanced chemical equation. - 3
Moles of product B
0.5551 mol × 0.5 = 0.2775 - 4
Mass of product B
0.2775 mol × 32 g/mol = 8.8815
How does this calculator work?
To convert reactant mass to product mass, divide the reactant mass by its molar mass to get moles, multiply by the product-to-reactant coefficient ratio from the balanced equation, then multiply by the product molar mass. This yields the theoretical product mass in grams, assuming complete reaction and 100% yield.
Formula
How this is calculated
A mass-to-mass stoichiometry problem follows three steps: grams of A to moles of A, moles of A to moles of B, and moles of B back to grams of B. First the known mass of reactant A is divided by its molar mass M_A (g/mol) to obtain moles of A. The molar mass is the sum of the atomic masses in the species formula.
Next the moles of A are multiplied by the mole ratio, the stoichiometric coefficient of B divided by the coefficient of A taken directly from the balanced chemical equation. This converts the amount of substance from A to B. Finally moles of B are multiplied by the molar mass of B to give the predicted mass of product in grams.
The calculation assumes the reaction goes to completion with A as the limiting reagent and 100% yield; real yields are lower. Coefficients must come from a balanced equation, and molar mass of A and the coefficient of A must be non-zero to avoid division by zero. All masses are in grams and molar masses in grams per mole.
Frequently asked questions
They are the stoichiometric coefficients in front of each species in the balanced chemical equation. Always balance the equation first before reading them off.
No. It gives the theoretical mass assuming complete reaction and that A is fully consumed. Multiply the result by the fractional yield to estimate actual product, and check that A is the limiting reagent.
Add the atomic masses of every atom in the chemical formula. For example water (H2O) is about 2×1.008 + 16.00 = 18.015 g/mol.
Also known as
TG we-Calculate Editorial Team. (2026). Stoichiometry Mass-to-Mass Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/stoichiometry-mass-to-mass-calculator
TG we-Calculate Editorial Team. "Stoichiometry Mass-to-Mass Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/stoichiometry-mass-to-mass-calculator.
TG we-Calculate Editorial Team, "Stoichiometry Mass-to-Mass Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/stoichiometry-mass-to-mass-calculator
@misc{wecalculate_stoichiometry_mass_to_mass_calculator, title = {Stoichiometry Mass-to-Mass Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/stoichiometry-mass-to-mass-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?