How does entropy relate to osmosis and diffusion?
Both processes function to spread solute particles out (achieve equilibrium) - this represents the greatest amount of energy dispersal in the system.
Due to the kinetic nature of particles, their constant motion bumps particles around (i.e. think Brownian motion).
The likelihood of particles being moved from a region where they are scarce to a region where they are more common is unlikely, whereas the likelihood of particles moving from a region where they are dense to a region where they are scarce is more likely.
An imbalance in concentration of solutes in solution can be seen as energetically-dense on one side, and the processes of diffusion and osmosis are natural processes that function without an input of energy to disrupt the enegetically-dense side, maximizing energy dispersal (i.e. entropy).
Entropy is the tendency for things to spontaneously spread out and go from a highly ordered concentrated state to less ordered diffused state.
Entropy is the basis of the second law of thermodynamics. Heat goes from a high energy state that is highly localized to a low energy state that has a lower density, or diffused.
Diffusion is a direct result of the second law or entropy. The molecules spread out in all directions lowering the concentrations of he molecules in the original space.
Osmosis is diffusion that is controlled by a membrane. The membrane allows diffusion in only one direction. Because of the size of the openings in the membrane small molecules can diffuse through the membrane but larger molecules cannot
The second law of thermodynamics or entropy indicates that the entire universe is becoming more diffuse. The rate of the expansion of the universe is increasing causing the universe to become lower in heat heat energy/density. The total heat energy of the universe will remain constant but will become so diffused that there will be no useable matter or energy left.