Osmosis

• What is osmosis?

  Osmosis is the movement of water molecules across a partially permeable membrane.
• What type of membrane is involved in osmosis?

  A partially permeable membrane is involved in osmosis.
• How does osmosis relate to diffusion?

  Osmosis is a special case of diffusion specifically for water molecules.
• What can pass through a partially permeable membrane?

  Only tiny molecules, like water, can pass through a partially permeable membrane.
• Why do water molecules move both ways through the membrane during osmosis?

  Water molecules move randomly all the time, allowing movement in both directions.
• What happens to the concentration of a strong sugar solution during osmosis?

  The strong sugar solution becomes more dilute as water moves into it.
• What is the net flow of water during osmosis?

  There is a steady net flow of water into the region with fewer water molecules.
• What is the definition of osmosis in terms of diffusion?

  Osmosis is a type of diffusion involving the passive movement of water particles.
• What is the procedure for the osmosis experiment using potato cylinders?

  1. Cut potato into identical cylinders.
  2. Prepare beakers with different sugar solutions (e.g., pure water, 1 mol/dm³).
  3. Measure the mass of the cylinders.
  4. Leave cylinders in solutions for 24 hours.
  5. Dry and measure their masses again.
  6. Calculate percentage change in mass.
  7. Identify dependent variable (chip mass) and independent variable (sugar concentration).
  8. Keep other variables constant for a fair test.
• What could cause errors in the osmosis experiment?

  Errors may arise if potato cylinders are not fully dried or if water evaporates from beakers.
• How can you reduce the effect of errors in the osmosis experiment?

  You can reduce errors by repeating the experiment and calculating a mean percentage change.
• What does a positive percentage change in mass indicate in the osmosis experiment?

  A positive percentage change indicates that the potato cylinders have drawn in water by osmosis.
• What does a negative percentage change in mass indicate in the osmosis experiment?

  A negative percentage change indicates that the potato cylinders have lost water by osmosis.
• How can you modify the osmosis experiment to test the effect of salt solutions on potato chips?

  • Use different concentrations of salt solutions instead of sugar solutions.
  • Follow the same procedure as with sugar solutions.
  • Measure the effect on potato chip mass.