Osmotic Pressure Calculator

Calculate the osmotic pressure of a solution using the van 't Hoff equation.

Enter the solution's molarity, temperature, and van 't Hoff factor to compute osmotic pressure. Supports multiple units.

0.08206 L·atm·K⁻¹·mol⁻¹
Osmotic Pressure Examples

See how osmotic pressure is calculated for different solutions.

NaCl Solution at Room Temperature

osmotic-pressure

Calculate the osmotic pressure of a 0.2 M NaCl solution at 25°C (i = 2, unit: atm).

Molarity (M): 0.2

Temperature: 25 °C

van 't Hoff Factor (i): 2

Result Unit: Atmospheres (atm)

Glucose Solution in Kelvin

osmotic-pressure

Find the osmotic pressure of a 1.0 M glucose solution at 298 K (i = 1, unit: Pa).

Molarity (M): 1

Temperature: 298 K

van 't Hoff Factor (i): 1

Result Unit: Pascals (Pa)

CaCl₂ Solution at 10°C

osmotic-pressure

Calculate the osmotic pressure of a 0.5 M CaCl₂ solution at 10°C (i = 3, unit: bar).

Molarity (M): 0.5

Temperature: 10 °C

van 't Hoff Factor (i): 3

Result Unit: Bar (bar)

Urea Solution at 37°C

osmotic-pressure

Find the osmotic pressure of a 0.3 M urea solution at 37°C (i = 1, unit: atm).

Molarity (M): 0.3

Temperature: 37 °C

van 't Hoff Factor (i): 1

Result Unit: Atmospheres (atm)

Other Titles
Understanding Osmotic Pressure: A Comprehensive Guide
Learn the science, math, and real-world uses of osmotic pressure.

What is Osmotic Pressure?

  • Definition and Physical Meaning
  • Role in Chemistry and Biology
  • Key Factors Affecting Osmotic Pressure
Osmotic pressure is the pressure required to prevent the flow of solvent molecules through a semipermeable membrane from a dilute solution into a more concentrated one. It is a fundamental concept in chemistry, biology, and medicine.
Osmosis in Everyday Life
Osmosis explains why plant roots absorb water, how kidneys filter blood, and why saline solutions are used in medicine.

Common Osmosis Scenarios

  • Why do plant cells swell in pure water?
  • How does intravenous saline prevent cell damage?

Step-by-Step Guide to Using the Osmotic Pressure Calculator

  • Inputting Solution Details
  • Choosing Units and Factors
  • Interpreting Results
How to Use the Calculator
Enter the solution's molarity, temperature, and van 't Hoff factor. Select the desired units for temperature and pressure. Click 'Calculate' to get the osmotic pressure instantly.
The calculator automatically applies the correct gas constant (R) based on your selected pressure unit.

Step-by-Step Examples

  • Calculating osmotic pressure for a NaCl solution at 25°C.
  • Finding osmotic pressure in Pascals for a glucose solution.

Real-World Applications of Osmotic Pressure

  • Biological Systems
  • Industrial and Laboratory Uses
  • Medical and Pharmaceutical Applications
Osmotic Pressure in Biology
Osmotic pressure governs water movement in cells, plant turgor, and kidney filtration.
Industrial and Medical Relevance
It is crucial in dialysis, food preservation, and drug formulation.

Applications in Practice

  • Dialysis machines use osmotic pressure to filter blood.
  • Reverse osmosis in water purification.

Common Misconceptions and Correct Methods

  • Misunderstanding van 't Hoff Factor
  • Confusing Units and Constants
  • Ignoring Temperature Conversions
Avoiding Calculation Errors
Always use the correct van 't Hoff factor for your solute. Double-check temperature units and ensure you use the right gas constant for your selected pressure unit.
Convert Celsius to Kelvin by adding 273.15 before calculation.

Common Mistakes

  • Using i = 2 for NaCl, not 1.
  • Selecting R = 0.08206 for atm, not for Pa.

Mathematical Derivation and Examples

  • The van 't Hoff Equation
  • Unit Conversions
  • Worked Example Calculations
The van 't Hoff Equation
π = i × M × R × T, where π is osmotic pressure, i is van 't Hoff factor, M is molarity, R is the gas constant, and T is temperature in Kelvin.
Example Calculation
For a 0.2 M NaCl solution at 25°C (i = 2, R = 0.08206, T = 298.15 K): π = 2 × 0.2 × 0.08206 × 298.15 ≈ 9.78 atm.

Math in Action

  • Calculating osmotic pressure for CaCl₂ (i = 3).
  • Converting result from atm to Pa.