Loading VerChem
Preparing your chemistry tools...
Preparing your chemistry tools...
Solve stoichiometry problems with step-by-step solutions. Mass-mole conversions, limiting reagent, percent yield, and more.
Convert grams to moles
Quick Reference - Common Molar Masses:
Click any example to practice with our calculator
n = mass / M
mass = n × M
n = moles, M = molar mass
n₂/n₁ = coeff₂/coeff₁
From balanced equation coefficients
% Yield = (actual/theoretical) × 100
Measures reaction efficiency
Get answers in milliseconds with step-by-step solutions
See the complete solution process to learn as you calculate
Mass-mole, mole-mass, mass-mass, limiting reagent, yield
Built-in reference for accurate atomic masses
Precise calculations for laboratory work
Perfect for homework and exam preparation
Stoichiometry is the calculation of quantities of reactants and products in chemical reactions. It uses mole ratios from balanced equations to convert between masses, moles, and numbers of particles.
Divide the mass (in grams) by the molar mass (in g/mol). For example, 18g of water (H₂O, molar mass 18.015 g/mol) = 18/18.015 = 0.999 mol.
The limiting reagent is the reactant that gets completely consumed first in a reaction, determining the maximum amount of product that can form. The other reactants are "in excess."
Percent yield = (actual yield / theoretical yield) × 100. Actual yield is what you measured; theoretical yield is calculated from stoichiometry. A yield over 100% suggests impurities or measurement error.
Make sure you're using the correct coefficients from your balanced equation. The mole ratio comes directly from these coefficients. If unsure, use our Equation Balancer tool first.
VerChem offers a complete suite of chemistry calculators