{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"osmotic-pressure"},"result":{"entity_type":"calculator","id":"osmotic-pressure","calculator_id":"osmotic-pressure","canonical_url":"https://tttkmbb.com/chemistry/osmotic-pressure","name":"Osmotic Pressure Calculator","title":"Osmotic Pressure Calculator – van 't Hoff Equation π = iMRT in atm, kPa, bar and mmHg","category":"chemistry","category_name":"Chemistry","tool_name":"calculate_osmotic_pressure","featured_mcp_tool":false,"description":"Computes the osmotic pressure of a solution from molarity, van 't Hoff factor and temperature with the van 't Hoff equation π = i·M·R·T, or solves the molarity (and the solute's molar mass, given its mass concentration) from a measured osmotic pressure.","use_when":"You need the osmotic pressure of a solution of known concentration, or the concentration or molar mass of a solute (e.g. a protein or polymer) from an osmometry measurement.","do_not_use_when":"You need freezing-point depression or boiling-point elevation (use colligative-properties), or the solution is concentrated enough that activity effects matter (roughly above 0.1–0.5 mol/L for electrolytes).","inputs":[{"name":"molarity_mol_per_l","label":"Molarity","type":"number","required":false,"max":100,"exclusive_min":0,"description":"Molar concentration of the solute formula units in mol/L. 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Real electrolytes give slightly lower values (about 1.9 for 0.1 M NaCl) because of ion pairing."},{"q":"Why is osmotic pressure so large?","a":"Even 0.1 mol/L of dissolved particles exerts about 2.4 atm at 25 °C, because π depends on the number of particles like an ideal gas of the same concentration; blood plasma is about 0.3 osmol/L, roughly 7.6 atm."}],"tags":["osmotic pressure","van 't hoff equation","osmolarity","osmometry molar mass","colligative properties"],"related":[{"calculator_id":"colligative-properties","reason":"Freezing-point depression and boiling-point elevation for the same solution."},{"calculator_id":"molarity","reason":"Compute the molarity from solute mass and volume."},{"calculator_id":"ideal-gas-law","reason":"The van 't Hoff equation has the same form as PV = nRT."}],"links":{"html":"https://tttkmbb.com/chemistry/osmotic-pressure","markdown":"https://tttkmbb.com/chemistry/osmotic-pressure.md","json":"https://tttkmbb.com/chemistry/osmotic-pressure.json","api":"https://tttkmbb.com/api/v1/calculate/osmotic-pressure","schema":"https://tttkmbb.com/api/v1/calculators/osmotic-pressure","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T02:02:57Z","next_actions":[{"tool":"run_calculator","calculator_id":"osmotic-pressure","reason":"Run Osmotic Pressure Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/chemistry/osmotic-pressure.md"}}