Reaction Stoichiometry Calculator
Given a balanced equation's coefficients + moles of one species, compute moles of all others.
Result
Required moles
B: 2.000, C: 4.000, D: 0.000
From 4 mol A and equation 2A + 1B → 2C + 0D.
- Equation2A + 1B → 2C
- Moles A (basis)4
- Mole ratio2.000000
- Moles B needed2.000000
- Moles C produced4.000000
- Moles D produced0.000000
Step-by-step
- Equation: 2A + 1B → 2C.
- Mole ratio basis: 1 mol A = 0.5 mol B = 1 mol C = 0 mol D.
- For 4 mol A: needs 2.0000 B; produces 4.0000 C, 0.0000 D.
How to use this calculator
- Enter coefficients of the balanced equation.
- Enter moles of one reactant.
- Read what other species you need + produce.
About this calculator
Once an equation is balanced (e.g. 2H₂ + O₂ → 2H₂O), coefficient ratios = mole ratios. This calc takes the coefficients and one quantity, then scales: from 4 mol H₂, you need 2 mol O₂ and produce 4 mol H₂O. Note: this calc does not balance unbalanced equations — that requires formula parsing + linear-algebra. Use a dedicated chemistry tool (e.g. ChemAxon) for full balancing.
Frequently asked
By inspection for simple ones. For complex: linear algebra over element-count vectors. Online balancers handle full formula parsing.
Related calculators
Ideal Gas Law (PV = nRT)
Solve for any of P, V, n, T given the other three. R = 8.314 J/(mol·K).
Avogadro's Law (V₁/n₁ = V₂/n₂)
At constant T, P: volume scales with number of moles.
Atomic Mass from Isotopes Calculator
Σ (isotope mass × abundance fraction). Periodic-table atomic mass from isotope mix.
Henderson-Hasselbalch (Buffer pH)
pH = pKa + log([A⁻]/[HA]). Predict buffer pH from acid + conjugate base concentrations.
Half-Life ↔ Decay Constant
t½ = ln(2) / k. Convert between half-life and decay constant; predict remaining fraction.
Radioactive Decay (N = N₀ e^(−kt))
Quantity remaining after time t given decay constant k or half-life.