Calculate molarity of a solution
Exactchemistry_molarityDeterministic and authoritative — the canonical answer for this input.
Calculate molarity (mol/L) of a solution, fully locally (no upstream call), from exactly one of three input shapes: (1) mass_concentration_g_per_l + formula/molar_mass; (2) moles + volume; (3) mass (+ purity_pct) + formula/molar_mass + volume. The three path selectors are mutually exclusive — passing more than one returns an invalid-input result, not a silent path choice. Molar mass is resolved from a molecular formula OR given explicitly (also mutually exclusive). Insufficient/contradictory inputs -> confidence 0.0. Batch via chemistry_molarity_batch. Charges 1 cost_unit.
Parameters
molesnumberoptionalMoles of solute (path: moles + volume).
massnumberoptionalMass of solute (path: mass + formula/molar_mass + volume).
mass_unitstringoptionalMass unit: kg, g, mg, ug, ng. Default 'g'.
formulastringoptionalMolecular formula of the solute (e.g. 'NaCl'), used to resolve molar mass locally.
molar_massnumberoptionalMolar mass in g/mol — mutually exclusive with `formula` (pass one, not both).
purity_pctnumberoptionalSolute purity percent applied to the mass path. Default 100.
mass_concentration_g_per_lnumberoptionalMass concentration in g/L (path: mass_concentration + molar_mass; no volume needed).
volumenumberoptionalSolution volume (paths needing volume).
volume_unitstringoptionalVolume unit: L, dL, mL, uL. Default 'L'.
Call it
curl -X POST https://api.snipget.ai/v1/chemistry/molarity \
-H "Authorization: Bearer sk_live_..." \
-H "Content-Type: application/json" \
-d '{"mass":5.844,"formula":"NaCl","volume":1,"volume_unit":"L"}'The Batch tab sends up to 1000 inputs in one call via /v1/chemistry/molarity/batch.
Example response
{
"is_valid": true,
"molarity_mol_per_l": 0.099995,
"method": "mass_and_volume",
"moles": 0.099995,
"molar_mass_g_per_mol": 58.4427,
"volume_l": 1
}FAQ
Why use this instead of working it out myself?
Molarity trips people up because you have to convert mass to moles using the right molar mass, then divide by volume in litres. This does all of that for you, resolving the molar mass straight from the formula, so you cannot fat-finger the atomic weights.
What inputs can I give it?
Three shapes: moles plus volume, mass plus a formula (or molar_mass) plus volume, or a mass concentration in g/L plus a formula. Pick exactly one shape, and within the mass path pass formula or molar_mass but not both: mixing shapes or giving both is rejected as ambiguous, returning confidence 0 with a why_invalid reason. You can set mass_unit (kg, g, mg, ug, ng), volume_unit (L, dL, mL, uL), and a purity_pct for the mass path.
Is the answer exact?
Yes. This is a deterministic calculation with no estimation, so the same inputs always return the same number. It runs fully offline and does not look anything up.
What does it not do?
It will not guess a molar mass from a compound name (give it the formula or the molar_mass directly), and it does not do dilutions or titration math. It only computes molarity.
What happens if I leave something out?
Missing, contradictory, or non-numeric inputs come back with confidence 0 and a why_invalid reason, not an error. For example, moles alone with no volume is rejected with an explanation.