Osmotic Pressure Calculator Formula

Understand the math behind the osmotic pressure calculator. Each variable explained with a worked example.

Formulas Used

Osmotic Pressure

osmotic_pressure = vant_hoff * molarity * 0.08206 * (temp_celsius + 273.15)

Osmotic Pressure

osmotic_kpa = vant_hoff * molarity * 0.08206 * (temp_celsius + 273.15) * 101.325

Variables

VariableDescriptionDefault
vant_hoffVan't Hoff Factor (i)1
molarityMolarity(M)0.1
temp_celsiusTemperature(C)25

How It Works

How to Calculate Osmotic Pressure

Formula

pi = i × M × R × T

Where R = 0.08206 L-atm/mol-K and T is in Kelvin.

Worked Example

0.1 M glucose at 25C (i=1).

vant_hoff = 1molarity = 0.1temp_celsius = 25
  1. 01T = 25 + 273.15 = 298.15 K
  2. 02pi = 1 × 0.1 × 0.08206 × 298.15
  3. 03pi = 2.447 atm

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