Osmosis

Question 1

What is osmosis?

Answer 1

• The movement of water across a partially permeable membrane from high to low water potential.

Question 2

What is water potential?

Answer 2

• The pressure exerted by water molecules on a membrane or container.
• When a soluble is dissolved in water it is surrounded by water molecules.
• These water molecules are no longer ‘free’ to exert pressure on the membrane, container so potential decreases.

Question 3

What does a solution with a HIGH WATER POTENTIAL have?

Answer 3

• LOW CONCENTRATION of solute and a HIGH CONCENTRATION of water.

Question 4

What does a solution with a LOW WATER POTENTIAL have?

Answer 4

• HIGH CONCENTRATION of solute and a LOW CONCENTRATION of water.

Question 5

How do we measure WATER POTENTIAL?

Answer 5

• Measured in pascals
• Can be high enough to be measured in kilopascals or megapascals

Question 6

How many pascals in a kilopascal?

Answer 6

• There are 1000 pascals in a kilopascal

Question 7

How many pascals in a megapascal?

Answer 7

• There are 1,000,000 pascals in a megapascal.

Question 8

STAND TEMPERATURE

Answer 8

At standard pressure, the water potential of pure water is ZERO,
- The addition of solutes lower the water potential, makes it more NEGATIVE
- The solutions always have a water potential values that are NEGATIVE