WebToolArcPractical guide and verification
Use the tool first, then use these checks to interpret, verify and hand off the result without displacing the primary workflow.
Write the chemical formula exactly as intended
A missing subscript, parenthesis, hydrate separator, or element symbol changes the composition and molar mass. Compare the parsed element counts with the formula you meant to enter before using the result in a lab calculation. Capitalization matters because element symbols are case-sensitive.
Separate molar mass from sample mass
Molar mass describes grams per mole of the formula unit; it is not the mass of the sample sitting on a balance. When converting grams to moles or particles, verify that the measured sample corresponds to the same chemical formula and that any purity, solvent, or hydrate state is accounted for separately.
Use composition percentages as a verification tool
Mass percentages should add to approximately 100 percent apart from display rounding. A surprising percentage often reveals an incorrectly parsed element count or formula. Compare one simple compound by hand using periodic-table atomic masses before relying on a complicated formula or batch calculation.
Match significant figures to the source data
Atomic-weight tables contain more precision than many measured masses justify. Keep full calculator precision for intermediate work, then round according to the measurement or reporting standard you are following. Do not imply experimental accuracy merely because the displayed molar mass has many decimal places.