Definition of osmotic pressure.make animation for movement of water molecules

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Osmosis is the movement of water molecules through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. Here we see a container divided by a semipermeable membrane, with pure water on the left and a sugar solution on the right. Water molecules move randomly, but there is a net movement from the pure water side toward the solution side. At the molecular level, water molecules move randomly in all directions through the membrane pores. However, because there are more water molecules on the pure water side, more molecules cross from left to right than from right to left. This creates a net flow toward the higher solute concentration, which is the driving force of osmosis. Osmotic pressure is defined as the pressure that must be applied to a solution to prevent the inward flow of water across a semipermeable membrane. When a solution is separated from pure water by a membrane that allows water but not solute particles to pass through, water molecules naturally move from the pure water side to the solution side. This creates a pressure difference that we call osmotic pressure. At equilibrium, the system reaches a stable state where the rate of water movement in both directions across the membrane becomes equal. The osmotic pressure can be calculated using the van't Hoff equation: pi equals i times M times R times T, where pi is the osmotic pressure, i is the van't Hoff factor, M is the molarity of the solution, R is the gas constant, and T is the absolute temperature.