Required practicle 3 - Osmosis

Question 1

What is osmosis?

Answer 1

Diffusion of water from an area of high concentration of water to an area of low concentration of water across a partially permeable membrane

Question 2

What is the method for measuring rate of diffusion?

Answer 2

• Peel potatoes and cut into quarters with equal diameters
• Cut the potatoes using a cork boarer to make sure all cylinders have the same diameter
• use a scalpel to cut all the same length (around 3cm)
• measure and record the mass of each cylinder using a balance
• place each cylinder into test tube and add 10cm^3 of a 0.5 molar sugar solution to the first test tube, 0.25 to the second and distilled water to the third
• leave overnight to allow osmosis to occur
• gently roll on paper towel to remove any surface moisture then measure length and mass again
• record and compare % change

Question 3

What is the percentage change equation?

Answer 3

Change in value/ original X 10