Osmosis

Cards (8)

  • Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
  • Water may move across cell membranes via osmosis
  • Osmosis is the passive movement of water particles from an area of high water concentration to an area of low water concentration
  • During osmosis water particles pass through both ways but the net movement flows to the more concentrated solution
  • Osmosis practical
    • Cut a potatoes into identical cylinders
    • Measure the mass of the potatoes
    • Place one in pure water and another in a concentrated sugar solution (1 mol/dm3) and have a few concentrations between and leave for 24 hours
    • The the potatoes out and dry with a paper towel and measure the masses
  • Osmosis practical
    • If the mass of the potato decreased that means that water has been drawn out meaning that the sugar solution was more concentrated than the potatoes sugar levels
  • Osmosis practical
    • If the mass of the potato increased that means that water has been taken in meaning that the sugar solution was less concentrated than the potatoes sugar levels
  • Osmosis practical
    • Errors could occur if the potatoes were not fully dried and the excess gave a higher mass, or if water evaporated from the beakers changing the concentration of the sugar solution
    • The results could be more accurate by repeating the experiment and calculating the mean percentage change of weight