Osmosis Required Practical

Question 1

Mnemonic to remember method: COMPLEMP. What does the C stand for?

Answer 1

Cork borer. Use a cork borer to take three samples of potato of the same diameter. Use the same potato to make results more comparable

Question 2

What does O stand for?

Answer 2

On a white tile, cut the skin off the ends of the potato samples and use a ruler to cut the potato samples to 3 cm

Question 3

What does M stand for?

Answer 3

Measure the mass of each potato sample using precise scales and record it in your results table

Question 4

What does P stand for?

Answer 4

• Prepare boiling tubes with samples.
• Prepare 3 boiling tubes and place a potato sample in each 1

Question 5

What does the L stand for?

Answer 5

• Liquids added - add distilled water and sugar solutions
• Use a measuring cylinder to measure 10 cm^3 of distilled water.
• Put the water in a boiling tube and label it to avoid mixing it up. Seal boiling tube with a bung to avoid evaporation
• Repeat steps adding 0.25M sucrose solution and 0.5M sucrose solution to the remaining boiling tubes

Question 6

What does the E stand for?

Answer 6

Evening - leave tubes sealed overnight

Question 7

What does the M stand for?

Answer 7

• Measure the length and mass changes
• Remove the potato from the first boiling tube and quickly roll on a paper towel to remove excess liquid
• Measure the new length of the sample using a ruler and record it in your results table
• Measure the new mass of the potato with the scale and record it in your results table
• Repeat steps with two other boiling tubes

Question 8

What does the P stand for?

Answer 8

• Percentage change calculations in the table
• Use your results in the table to calculate the difference in length and weight by subtracting the new value by the original value
• Calculate he percentage change by dividing the change in mass by the original mass and multiplying by 100