Advanced Reaction Extent Calculator

Measure reaction progress with fast stoichiometric clarity. Review feasible extent limits, compositions, and concentration changes. Export polished tables and charts for labs today easily.

Calculator Inputs

The page stays single-column, while the calculator cards use 3 columns on large screens, 2 on smaller screens, and 1 on mobile.

This field mirrors the submitted extent_value input.
Reaction preview: N2 + 3 H2 → 2 NH3
Use negative coefficients for reactants and positive coefficients for products. Example: N2 = -1, H2 = -3, NH3 = 2.

Species 1

Species 2

Species 3

Example data table

This worked example uses ammonia synthesis with ξ = 0.8 mol and volume = 10 L.

Species νi Initial moles Final moles Concentration
N2 -1 1.0 0.2 0.02 mol/L
H2 -3 4.0 1.6 0.16 mol/L
NH3 2 0.0 1.6 0.16 mol/L

Formula used

Reaction extent links stoichiometry to composition changes. For each species, final moles are determined from initial moles and the signed stoichiometric coefficient.

ni = ni,0 + νi ξ

Feasible extent limits keep every final mole value nonnegative.

If νi > 0, then ξ ≥ -ni,0 / νi If νi < 0, then ξ ≤ ni,0 / |νi|

When the basis is reactant conversion, extent is derived from the selected reactant.

Xj(%) = (|νj| ξ / nj,0) × 100 ξ = (Xj / 100) × (nj,0 / |νj|)

Additional reported values use these standard relations.

yi = ni / Σni Ci = ni / V mi = ni Mi Yield(%) = ((nactual - n0) / (ntheoretical,max - n0)) × 100

How to use this calculator

  1. Enter the reaction label and choose how many species will participate.
  2. For each active species, provide its name, signed stoichiometric coefficient, initial moles, and optional molar mass.
  3. Choose either direct extent input or reactant conversion mode.
  4. Optionally enter system volume for concentrations and actual product moles for yield estimation.
  5. Press Calculate Reaction Extent to view the result block above the form, inspect tables, and export CSV or PDF files.

FAQs

1) What does reaction extent mean?

Reaction extent measures how far a reaction has progressed. It converts stoichiometric coefficients into actual mole changes for every species at the same time.

2) Why are reactants negative and products positive?

Signed coefficients make one equation work for all species. Negative values decrease reactants, while positive values increase products as extent grows.

3) Can the extent be negative?

Yes, if your starting mixture already contains products and the reverse direction is feasible. The valid range is limited by nonnegative final moles.

4) How is the limiting reactant identified?

The calculator compares n0/|ν| for all reactants. The smallest value defines the maximum forward extent and identifies the limiting reactant.

5) Why did the calculator reject my value?

The entered extent or conversion probably makes one species go negative. The tool shows the feasible extent window to keep the mixture physically valid.

6) What is the benefit of entering volume?

Volume lets the tool convert final mole amounts into concentrations. Leave it blank if you only need stoichiometric mole balances.

7) How is the optional yield estimate handled?

Yield is estimated from the tracked product using your actual final product moles versus the theoretical maximum product gain under complete limiting-reactant conversion.

8) What does the Plotly graph show?

One chart compares initial and final moles. The second chart shows how each species changes across the entire feasible extent range.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.