water potential

• solute

  = substance dissolved in a solvent (water)
• water potential

  = pressure exerted by water molecules as they collide with a membrane or container.

  • measure in pascals
  • pure water= 0kPa
  • the presence of a solute lowers the water potential below 0, all solutions have negative water potentials- the more concentrated the solution the more negative the water potential.
• solutions of different concentrations, have different water potentials, are separated by a partially permeable membrane, water molecules can move between solutions but the solutes can't.

  • there will be a net movement of water from the solution with the higher water potential to the solution with lower water potential. Will continue until equilibrium.