Osmotic pressure calculator
Osmotic pressure behaves like an ideal gas pressure exerted by the dissolved particles.
mol/L
Osmotic pressure
7.736bar
- Same pressure
- 7.635 atm
- Same pressure
- 773 619 Pa
- Osmolarity
- 0.3000 osmol/L
Show the working
- Molarity = 0.15
- Van't Hoff factor = 2
- Temperature = 37
- tk = 37 + 273.15 = 310.15
- Osmolarity = 2 * 0.15 = 0.3
- Same pressure = 2 * 0.15 * 1000 * Rgas * 310.15 = 773 619
- Osmotic pressure = 773 619 / 100000 = 7.736 19
- Same pressure = 773 619 / 101325 = 7.635 03
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- pi = i M R T, with M in mol per cubic metre
Physiological saline at 0.15 M NaCl and 37 degrees Celsius gives about 7.7 bar, which is why cells burst in pure water.