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Osmotic Pressure Calculator (π) - Colligative Property

Calculate osmotic pressure using the van 't Hoff equation for solutions at various temperatures. Chemistry calculator for physical chemistry, biology, pharmaceutical, and medical applications. Supports electrolytes and non-electrolytes with van 't Hoff factor.

Osmotic Pressure Formula

π = M · R · T · i

Variables:

  • πOsmotic pressure (atm)
    Osmotic pressure (atm)
  • MSolution molarity (mol/L)
    Solution molarity (mol/L)
  • RIdeal gas constant (0.082 L·atm/mol·K)
    Ideal gas constant (0.082 L·atm/mol·K)
  • TAbsolute temperature (Kelvin)
    Absolute temperature (Kelvin)
  • iVan't Hoff factor (1 for non-electrolytes)
    Van't Hoff factor (1 for non-electrolytes)

How to Use the KalkuLab Osmotic Pressure Calculator

  1. 1

    Enter Concentration

    Enter the molarity (M) of the solution.

  2. 2

    Enter Temperature

    Enter the temperature in Celsius or Kelvin (the calculator will convert if needed).

  3. 3

    Set the van't Hoff Factor

    For non-electrolytes (sugar, urea), i = 1. For electrolytes, calculate i = 1 + (n-1)α.

Examples

Glucose Osmotic Pressure

Problem:

Calculate the osmotic pressure of a 0.1 M glucose solution at 27°C.

Solution:
  1. 1.Given: M = 0.1, T = 27°C = 300 K, i = 1 (non-electrolyte), R = 0.082
  2. 2.Formula: π = M · R · T · i
  3. 3.Calculate: π = 0.1 × 0.082 × 300 × 1
  4. 4.Result: π = 2.46 atm
Result:2.46 atm

The osmotic pressure of this solution is 2.46 atm.

Frequently Asked Questions

What is osmotic pressure?
Osmotic pressure is the minimum pressure that must be applied to a solution to prevent the inward flow of pure solvent through a semipermeable membrane.
What is the van't Hoff factor?
A factor that accounts for the number of particles formed when an electrolyte dissolves. The more ions produced, the greater the colligative effect.

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References