Table of Contents
What is Osmotic Pressure?
Osmotic Pressure – Equation: The osmotic pressure is the pressure that is necessary to prevent a solution from passing through a semipermeable membrane into a more concentrated solution.
Osmotic Pressure Equation
The osmotic pressure equation states that the osmotic pressure of a solution is directly proportional to the number of moles of solute particles present in the solution. The equation is written as:
\mathrm{P}_{\mathrm{osmotic}} = \frac{\mathrm{R}T}{n}\mathrm{A}
where:
- P osmotic is the osmotic pressure
- R is the gas constant
- T is the temperature
- n is the number of moles of solute particles
- A is the cross-sectional area of the solution
What Exactly is Osmosis?
Osmosis is the natural process of diffusion through a semipermeable membrane. In osmosis, water molecules move from an area of high concentration to an area of low concentration until the concentration is equal on both sides of the membrane.
Understanding the Osmotic Pressure
The osmotic pressure is the pressure that is exerted by a solution on a semipermeable membrane in order to prevent the passage of solvent molecules through the membrane. In other words, it is the pressure that is exerted by a dissolved particle on the surrounding solvent in order to prevent the solvent from passing through the membrane.
Osmotic Pressure Example
If you placed a beaker of water in a sealed container with a teaspoon of salt, the water would evaporate until the concentration of salt in the remaining water reached about 26%. The osmotic pressure of the water at this concentration would be about 260 atmospheres.
Osmotic Pressure Example on Wilting Plants
If a plant is wilting, one reason may be that the water potential in the plant is higher than the water potential in the soil. In this case, water will flow from the soil into the plant, and the plant will become more hydrated. If the water potential in the plant is lower than the water potential in the soil, water will flow from the plant into the soil, and the plant will become less hydrated. Osmotic pressure is the force that drives water molecules from one area to another.
