Limiting reagent calculator (with steps)

Balance a reaction, convert inputs, and find the limiting reagent with clear step-by-step math.

Common reactions (presets)

Chemical equation

Auto-balance (nullspace RREF) i Keep on to derive coefficients from elements; toggle off to use your own stoichiometric coefficients.

Significant figures Round results to match the significant figures of your inputs.

Species	Side	Coeff	Molar mass (g/mol)	Amount	Type	Purity (%)

How to use this calculator effectively

This guide helps you use Limiting reagent calculator (with steps) in a repeatable way: define a baseline, change one variable at a time, and interpret outputs with explicit assumptions before you share or act on results.

How it works

The page applies deterministic logic to your inputs and shows rounded output for readability. Treat it as a comparison workflow: run one baseline case, adjust a single parameter, and measure both absolute and percentage deltas. If a result seems off, verify units, time basis, and sign conventions before drawing conclusions. This approach keeps your analysis reproducible across teammates and sessions.

When to use

Use this page when you need a fast estimate, a classroom check, or a practical what-if comparison. It works best for planning and prioritization steps where you need direction and magnitude quickly before investing in deeper modeling, manual spreadsheets, or formal external review.

Common mistakes to avoid

Changing multiple parameters at once, which hides the true cause of output movement.
Mixing units (percent vs decimal, monthly vs yearly, gross vs net) across scenarios.
Comparing with another tool without aligning defaults, constants, and rounding rules.
Using rounded display values as exact downstream inputs without re-checking precision.

Interpretation and worked example

Run a baseline scenario and keep that result visible. Next, modify one assumption to reflect your realistic alternative and compare direction plus size of change. If the direction matches your domain expectation and the size is plausible, your setup is usually coherent. If not, check hidden defaults, boundary conditions, and interpretation notes before deciding which scenario to adopt.

Frequently asked questions

How does this calculator determine the limiting reagent?

The tool converts each reactant to effective moles from unit and purity. It compares n0/ν across reactants, and the smallest value becomes the limiting reagent. The step log shows each conversion and ratio.

Can it estimate percent purity from a measured product mass?

Yes. Enter the suspect reactant mass, choose a target product, and add measured product mass. The tool back-solves product moles, scales by coefficients, and reports percent purity with steps.

What should I do first on this page?

Start with the minimum required inputs or the first action shown near the primary button. Keep optional settings at defaults for a baseline run, then change one setting at a time so you can explain what caused each output change.

Why does this page differ from another tool?

Different pages often use different defaults, units, rounding rules, or assumptions. Align those settings before comparing outputs. If differences remain, compare each intermediate step rather than only the final number.

How reliable are the displayed values?

Values are computed in the browser and rounded for display. They are good for planning and educational checks, but for regulated or high-stakes decisions you should validate assumptions with official guidance or professional review.

How it's calculated

From balanced equation and masses → moles; smallest moles limits the reaction.
Computes theoretical yield for selected product.
Share URL preserves inputs and coefficients.