osmotic pressure

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osmotic pressure

A student observes osmotic pressure in a simple laboratory demonstration.

Definition
  1. Noun:
    • (Physical Chemistry) The pressure required to prevent osmosis: Osmotic pressure is the minimum pressure that must be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is a colligative property, meaning it depends on the concentration of solute particles, not their identity.
Usage Examples
  • Noun:
    • The osmotic pressure of a concentrated sugar solution is quite high.
    • Plant cells rely on osmotic pressure to maintain their turgor and structural rigidity.
    • In medical treatments like dialysis, understanding osmotic pressure is crucial.
Advanced Usage
  • Calculating Osmotic Pressure: Often described by the van 't Hoff equation: Π = iCRT, where Π is osmotic pressure, i is the van 't Hoff factor, C is molar concentration, R is the gas constant, and T is temperature.

    • Scientists calculated the osmotic pressure to determine the molecular weight of the polymer.
  • Reverse Osmosis: A process where external pressure greater than the osmotic pressure is applied to force solvent from a concentrated solution to a dilute one.

    • Desalination plants use reverse osmosis, applying pressure that exceeds the natural osmotic pressure of seawater.
Variants and Related Words
  • Osmosis (n): The spontaneous net movement of solvent molecules through a semipermeable membrane into a region of higher solute concentration.

    • Water moves into the root cells by osmosis.
  • Osmotic (adj): Relating to or having the properties of osmosis.

    • The cell experienced an osmotic shock when placed in pure water.
  • Oncotic Pressure (n): A form of osmotic pressure exerted by proteins, particularly in blood plasma.

    • Albumin is a major contributor to the blood's oncotic pressure.
Synonyms
  • Solute Potential (in plant and soil sciences, a related but not identical concept).
  • Osmotic Potential.
Related Phrases and Concepts
  • Osmotic Gradient: The difference in solute concentration across a membrane, which drives osmosis.

    • The kidney uses an osmotic gradient to concentrate urine.
  • Osmotic Balance: The state where the osmotic pressure inside and outside a cell is equal, preventing net water movement.

    • Marine organisms have adaptations to maintain osmotic balance in salty water.
osmotic pressure

A student observes osmotic pressure in a simple laboratory demonstration.

Noun
  1. (physical chemistry) the pressure exerted by a solution necessary to prevent osmosis into that solution when it is separated from the pure solvent by a semipermeable membrane