Topic 1 Osmosis % Flashcards
Definition of osmosis
Movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration
What is a partially permeable membrane
Membrane with very small holes in it the only tiny water molecules can fit through it
Where is the steady net flow of water to
The side with fewer water molecules and more solutes
Osmosis practical (steps 1-3)
1)Cut potato into identical cylinders and get some beakers with different sugar solutions
One should be pure water and another should be very concentrated sugar solution
2)Measure the mass of the cylinders then leave one cylinder in each beaker for 24 hours
3) Try them with a paper towel and measure the mass again

Errors that can occur
If the potato cylinder is not fully dried the excess water would give a higher mass or if water evaporated from the bakers the concentrations of the sugar solutions will change
What does it mean if the mass of the potato cylinder increases
The potato had a higher solute concentration than in the water so drew in water via osmosis
What does it mean if the potato decreased in mass
The water had a highest value concentration so water was lost from the potato via osmosis
