Osmosis Praticle: Effect on Potoatoes

Question 1

Potato Praticle:

Answer 1

1) Peel the potato = skin can affect osmosis.
2) Use a cork borer to produce 3 cylinders of potato = same diameter.
3) Use a scalpel to trim the cylinders to the same length (about 3cm).
4) Measure the length of the cylinder using a ruler and a mass of the cylinder using a balance.

Question 2

Test Tubes pouring:

Answer 2

6) Place each cylinder into a test tube.
7) Add 10cm^3 of a 0.5 molar sugar solution to the first test tube.
8) Add 10cm^3 of 0.25 molar sugar solution to the 2nd test tube.
9) 10cm^3 of distilled water to the 3rd test tube.

Question 3

Why do we use distilled water instead of tap water?

Answer 3

• Distilled water contains no dissolved substances and they can affect the rate of osmosis.

Question 4

Continued steps:

Answer 4

• Leave the potato cylinders over night to allow osmosis to take place.
• Remove the potato cylinders and gently roll them onto a paper towel to remove any surface moisture.
• Measure the mass and length of the potato cylinders.

Question 5

How do we calculate percentage change?

Answer 5

% change= (change in value/ original value) x 100

Question 6

Graph Results:

Answer 6

• In water the potato cylinder gains mass as water moves into it by osmosis.
• Concentrated sugar solution= cylinder looses mass as water moves out my osmosis.
• Where the line crosses the x axis= no change in mass.
  Reason?- Concentration outside of the cell is the same as the outside of the cell so no overall osmosis takes place.

Question 6

Graph Results:

Answer 6

• In water the potato cylinder gains mass as water moves into it by osmosis.
• Concentrated sugar solution= cylinder looses mass as water moves out my osmosis.
• Where the line crosses the x axis= no change in mass.
  Reason?- Concentration outside of the cell is the same as the outside of the cell so no overall osmosis takes place.