EDUCATION DECISION WORKBENCH
Compare stoichiometric reactant ratios, identify limiting material, calculate theoretical product, and disclose modeled excess.
Review output
Load the worked example to inspect realistic inputs, or enter anonymous, policy-approved information. Results remain in this browser tab until you copy or download them.
Transparent method
Available moles nᵢ = massᵢ divided by molar massᵢ. Reaction units ξᵢ = nᵢ divided by coefficientᵢ. The smallest ξᵢ is the limiting reaction extent ξ. Product moles equal ξ times the product coefficient, and theoretical mass equals product moles times product molar mass. Excess remaining equals max(0, available moles − ξ times coefficient) converted back to mass. A limiting label follows only from the entered pure-reactant mass model and balanced coefficients. Tied ratios indicate a stoichiometric mixture within the displayed precision. Theoretical product is an upper stoichiometric amount, so an experimental result should be discussed with percent yield, purity, equilibrium, competing reactions, transfer loss, and measurement uncertainty.
Confirm the question, variables, units, source data, measurement precision, and the model expected by the current course or laboratory. Keep an untouched copy of observations before excluding or transforming any value.
Run the worked example first, inspect every intermediate row, compare units and signs, and look for a result that conflicts with the graph, physical system, chemical equation, or learning objective.
Record the method, assumptions, units, rounding, data limitations, and any excluded observations. Compare the exported report with an independent calculation or approved reference before assessment or laboratory use.
How to interpret the result
Use this workbench after balancing a reaction when more than one reactant amount is known and a learner must identify which one constrains product formation. The ratio table makes the decision visible and also estimates leftover excess. It supports stoichiometry practice and laboratory planning discussions but does not predict actual yield, safe quantities, reaction completion, or waste handling.
For 2 H₂ + O₂ → 2 H₂O, the example converts 5.00 g hydrogen and 32.00 g oxygen to moles, divides each amount by its reactant coefficient, selects the smaller reaction extent, multiplies by the product coefficient, and converts product moles with 18.015 g/mol. Remaining excess mass is calculated from modeled consumption.
Available moles nᵢ = massᵢ divided by molar massᵢ. Reaction units ξᵢ = nᵢ divided by coefficientᵢ. The smallest ξᵢ is the limiting reaction extent ξ. Product moles equal ξ times the product coefficient, and theoretical mass equals product moles times product molar mass. Excess remaining equals max(0, available moles − ξ times coefficient) converted back to mass.
A limiting label follows only from the entered pure-reactant mass model and balanced coefficients. Tied ratios indicate a stoichiometric mixture within the displayed precision. Theoretical product is an upper stoichiometric amount, so an experimental result should be discussed with percent yield, purity, equilibrium, competing reactions, transfer loss, and measurement uncertainty.
Do not compare masses directly, use subscripts as coefficients, skip equation balancing, mix grams and milligrams, use an incorrect formula mass, ignore purity or hydrate form, or call the excess reagent unreacted in every real system. Preserve unrounded moles during calculation and round the final reported quantity according to course rules.
Learning boundary
This browser-local workbench calculates only from the entered model and observations. It cannot validate an experiment, balance an equation, establish causation, certify laboratory safety, diagnose learning, or replace the method required by a teacher, curriculum, laboratory, or institution.
Review checklist
Practical questions
No. The calculation runs in the current browser tab. Avoid personal information and retain laboratory data in the system authorized by the school.
Treat it as an editable analysis aid. Show your own reasoning, cite the required sources, follow academic-integrity rules, and use the method requested by your course.
No. Check dimensions, graph shape, assumptions, measurement uncertainty, significant figures, and whether another model explains the observations better.
YOUR NIRMION
