STEM PRACTICE AND EVIDENCE WORKBENCH
Group elemental composition evidence, show every atomic-mass contribution, and audit one repeated learner molar-mass total.
Review output
Load the worked example to inspect realistic inputs, or enter anonymous classroom or laboratory evidence. Results remain in this browser tab until you copy or download them.
Transparent method
Element contribution equals entered atomic mass times formula count. Substance molar mass equals the sum of every unique elemental contribution in its group. The learner total is compared with the unrounded sum within a tight numerical tolerance, while the report preserves each multiplication so a count, source, or addition error can be located. Supported means the repeated total agrees with the entered composition. Agreement depends on correct formula counts, element symbols, atomic-mass values, units, and convention. Review significant figures, parentheses, coefficients versus subscripts, waters of hydration, charge notation, isotope-specific questions, and whether the requested entity is a molecule or formula unit.
Confirm the question, source, units, notation, response coding, model assumptions, and review threshold. Keep an unchanged copy of the original evidence.
Run the worked example, inspect every intermediate row, and compare it with a hand calculation, diagram, representation, or approved subject method.
Record the method, assumptions, units, classifications, and flagged rows. Verify the editable report independently before educational or laboratory use.
How to interpret the result
Use after a chemical formula and atomic-mass convention are known and learners need visible composition evidence. It identifies contribution and summation errors. It does not parse a formula, choose atomic weights, handle parentheses or hydrates automatically, infer isotopic composition, validate a substance identity, or replace an authoritative periodic table.
Water contributes two hydrogen masses plus one oxygen mass for about 18.015 grams per mole. Carbon dioxide contributes one carbon and two oxygen masses for about 44.009. The review ammonia rows sum one nitrogen plus three hydrogens to about 17.031, so the repeated learner total 16 is flagged.
Element contribution equals entered atomic mass times formula count. Substance molar mass equals the sum of every unique elemental contribution in its group. The learner total is compared with the unrounded sum within a tight numerical tolerance, while the report preserves each multiplication so a count, source, or addition error can be located.
Supported means the repeated total agrees with the entered composition. Agreement depends on correct formula counts, element symbols, atomic-mass values, units, and convention. Review significant figures, parentheses, coefficients versus subscripts, waters of hydration, charge notation, isotope-specific questions, and whether the requested entity is a molecule or formula unit.
Do not multiply the whole formula by one subscript, omit elements inside parentheses, use atomic number as atomic mass, confuse a reaction coefficient with composition, round every contribution early, mix grams with grams per mole, or assume a correct sum proves the formula. Expand and inventory atoms before calculating.
Learning boundary
This browser-local workbench applies only the disclosed rules. It cannot diagnose a learner, certify an experiment, or replace teacher, laboratory, and safety judgment.
Review checklist
Practical questions
No. Processing occurs in the current browser tab. Avoid personal information and retain authoritative records only in the approved school system.
No. It describes entered evidence under one disclosed rule. Review reasoning, uncertainty, access, and several evidence sources.
Treat it as an editable calculation aid. Show your own reasoning, cite required sources, and follow course and academic-integrity rules.
YOUR NIRMION
