#osmotic-pressure

Colligative-properties chemistry maths as an API, computed locally and deterministically. The freezing-point endpoint computes the freezing-point depression ΔTf = i·Kf·m and the resulting lowered freezing point of a solution, from the molality, the cryoscopic constant (1.86 °C·kg/mol for water) and the van 't Hoff factor i — which is 1 for a non-electrolyte like sugar, about 2 for sodium chloride and about 3 for calcium chloride. The boiling-point endpoint computes the boiling-point elevation ΔTb = i·Kb·m and the raised boiling point, with the ebullioscopic constant (0.512 °C·kg/mol for water). The osmotic-pressure endpoint computes the van 't Hoff osmotic pressure Π = i·M·R·T from the molarity, the temperature and the van 't Hoff factor, the pressure that drives osmosis across a semipermeable membrane, returned in atmospheres, kilopascals and bar. Molality is in mol per kg of solvent, molarity in mol per litre of solution and temperature in kelvin. Everything is computed locally and deterministically, so it is instant and private. Ideal for chemistry-education, food-science, antifreeze, desalination and biology app developers, solution and de-icing tools, and STEM teaching. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is colligative properties of solutions; for a compound's molar mass use a molar-mass API and for dilution concentrations a dilution API.

api.oanor.com/colligative-api

Colligative-properties maths for solutions as an API, computed locally and deterministically. The osmotic endpoint computes the osmotic pressure by the van 't Hoff equation, π = i·M·R·T, from the molarity, the temperature and the van 't Hoff factor (the number of dissolved particles per formula unit — 1 for sugar, 2 for NaCl, 3 for CaCl₂), reported in atmospheres, bar and kilopascals, and also solves the molarity back from a measured pressure. The freezing endpoint computes the freezing-point depression, ΔTf = i·Kf·m, from the molality and the cryoscopic constant (1.86 °C·kg/mol for water), and the new freezing point. The boiling endpoint computes the boiling-point elevation, ΔTb = i·Kb·m, from the ebullioscopic constant (0.512 °C·kg/mol for water), and the new boiling point. Everything is computed locally and deterministically, so it is instant and private. Ideal for chemistry, biology and food-science tools, reverse-osmosis and desalination estimates, antifreeze and de-icing formulation, lab and education apps. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is colligative-properties chemistry; for solution dilution use a dilution API and for pH and buffers use a pH API.

api.oanor.com/osmosis-api