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General questions, feedback and suggestions go to contact@quemist.com. Privacy questions and data rights requests go to privacy@quemist.com. There is no form, no ticket system and no account required — a plain email is the whole mechanism.

Reporting a wrong value

This is the most valuable thing anyone sends, and it is worth explaining why. A wrong atomic mass does not sit still. It propagates into every molar mass containing that element, and from there into percent composition, stoichiometry, solution prep and any conversion that passes through moles. One bad digit in one data file can be wrong on several hundred pages at once. The same is true of a mistaken conversion factor or a reference table row.

A report that can be acted on quickly contains four things:

  • The exact page URL. For a calculator, copy the address bar rather than describing the inputs — the inputs are encoded in the URL, so pasting it reproduces your calculation exactly, including any value you typed and then forgot about.
  • The value shown. Copied verbatim, with whatever precision was displayed.
  • The value you believe is correct.
  • Where your value comes from. A named source is far more useful than a recollection: an IUPAC table, a NIST entry, a CODATA value, a named textbook and edition. Everything gets checked against a reference before it changes, so telling us which reference you used is what makes the check fast.

Some disagreements turn out not to be errors, and it is worth knowing which ones in advance. Molar masses here are summed from full-precision standard atomic weights, so they can differ in the third decimal place from a textbook that rounds atomic masses before adding them. Standard atomic weights themselves are periodically revised by IUPAC, so an older printed table and a current one can legitimately disagree. And a conversion factor that is exact by definition will not match one that has been rounded for a worked example. None of that makes a report unwelcome — a value that looks wrong to a careful reader is worth checking either way.

Other things worth sending

  • Broken pages. A link that goes nowhere, a page that fails to load, a table that renders unreadably on a phone. Say which browser and roughly what size of screen.
  • Something missing. A compound with no page, a conversion pair that does not exist, a reference table you expected to find. These are cheap to add when someone names a specific one.
  • Calculator behaviour. A formula the molar mass parser refuses, a case where the steps shown do not match the result, an input that produces something obviously nonsensical.
  • Accessibility problems. Anything that fails with a screen reader, at high zoom, or on keyboard navigation alone. The accessibility statement covers what has been addressed so far.

What this site cannot answer

Being direct about this saves everyone time. Quemist is a reference and a set of calculators; it is not a help desk, a tutor or a consultancy, and there is no chemist on the other end of the address offering advice on your particular problem.

  • Coursework. Homework problems, lab reports and exam questions will not be worked through by email. The how-to guides cover the standard procedures end to end with worked numbers, which is the honest version of that help.
  • Safety, handling, disposal, clinical or dosing questions. None of these are answered here in any form. They belong to the Safety Data Sheet for the specific material and to a qualified person on site. The disclaimer states this in full.
  • Whether a value is appropriate for your application. Whether a molar mass is precise enough for your method, or a tabulated value applies under your conditions, depends on context this site does not have.
  • Regulatory or citable confirmation. Nothing here is validated for use in a controlled or accredited process, and it should not be cited. Cite the IUPAC, NIST or CODATA source the value came from.

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