Osmotic Pressure Calculator
Calculate osmotic pressure using the van't Hoff equation: pi = MRT.
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Enter the molarity of the solution, the temperature in Kelvin, and the van't Hoff factor (i). For non-electrolytes, i = 1. For electrolytes, i equals the number of ions formed per formula unit. The calculator computes pi = iMRT.
About the Osmotic Pressure Calculator
Osmotic pressure is a colligative property that depends on the number of solute particles in solution. It plays a central role in biology (cell osmosis), medicine (IV solutions), and chemical engineering (reverse osmosis water purification). The van't Hoff equation pi = iMRT provides a straightforward calculation.
Frequently Asked Questions
What is osmotic pressure?
Osmotic pressure is the minimum pressure needed to prevent solvent from flowing into a solution through a semipermeable membrane. It is a colligative property that depends on solute concentration, not identity.
What is the van't Hoff factor?
The van't Hoff factor (i) accounts for dissociation. For non-electrolytes like glucose, i = 1. For NaCl, i is approximately 2 (Na+ and Cl-). For CaCl2, i is approximately 3.
What value of R should I use?
This calculator uses R = 0.08206 L atm/(mol K). If you need pressure in other units, convert after: 1 atm = 101.325 kPa = 760 mmHg.