Solvent: The substance present in the greater amount in a solution (e.g., water).
Solute: The substance present in the lesser amount in a solution (e.g., sugar).
Solution: The mixture of solvent and solute.
Example with Water and Sugar
Water molecules in a container with sugar molecules dissolved in it.
Solvent: Water
Solute: Sugar
Diffusion
Definition: The process by which particles spread from areas of high concentration to low concentration.
Example with gas molecules in a container: Over time, gas spreads evenly to fill the container.
Key Point: No barriers to movement mean particles evenly spread out due to random motion.
Concentration: Amount of particles per unit space.
High Concentration: Many particles per unit space.
Low Concentration: Few particles per unit space.
Experiment with Two Containers
Two containers connected by a door larger than both water and sugar molecules.
Initially, water molecules move freely in both directions with equal probability.
When sugar is added to one side (making it hypertonic), water moves to equalize concentrations (diffusion).
Hypertonic: High solute concentration.
Hypotonic: Low solute concentration.
Osmosis
A type of diffusion involving water and a semi-permeable membrane.
Semi-permeable Membrane: Allows only certain molecules (e.g., water) to pass through while blocking others (e.g., sugar).
Scenario:
Inside a membrane, high concentration of solute (hypertonic).
Outside, low concentration of solute (hypotonic).
Water moves from the hypotonic area to the hypertonic area to equalize concentrations.
Over time, water flow continues until equilibrium is reached.
Important Points
Osmosis: Specifically the movement of water through a semi-permeable membrane from low solute concentration (hypotonic) to high solute concentration (hypertonic).
Equilibrium is based on probabilities and the random motion of molecules.
Osmosis and diffusion are natural processes that aim to balance concentrations on either side of a membrane or within a container.
Summary
Diffusion: Any particle moving from high to low concentration.
Osmosis: The diffusion of water, especially through a semi-permeable membrane.
Both processes are essential for understanding how substances mix and interact in different environments.