potato osmosis

Question 1

aim

Answer 1

investigate the effect of different concentrations of sugar sol on the mass of potato due to osmosis

Question 2

IV

Answer 2

sucrose sol. conc.

Question 3

DV

Answer 3

%change in mass of potato

Question 4

control variables

Answer 4

• Volume of sucrose solution
• Time left in solution (e.g., 20 minutes)
• species of potato and size
• temperature
• removing excess water

Question 5

method

Answer 5

• Cut equal-sized potato cylinders
• measure their initial mass of each
• Place into test tubes containing different sucrose solutions
• Leave for 20-30 minutes
• Remove, dry, and reweigh
• Calculate percentage change in mass: final mass - initial mass / initial mass x100
• plot graph of sucrose conc. vs percentage change in mass

Question 6

results

Answer 6

• at 0.0M sucrose concentration (pure water) - enters the potato therefore mass increases
• at 1.0M - water leaves the potato and mass decreases

Question 7

how to know if the potato has reached eqm

Answer 7

there is no more change in mass the water potential inside and out is the same

Question 8

why is it important to keep the size of the potatoes the same

Answer 8

different sizes would have different surface areas and volumes affecting the rate of osmosis

Question 9

improvements

Answer 9

• use a balance with higher precision e.g 2-3D.P
• use a cork borer to cut identical cylinders
• dry potatoes the same way - avoid adding or removing extra water
• water bath to control temperatures more accurately