PAG 8 Osmosis investigations

Question 1

what must be ensured during this PAG?

Answer 1

the size of potato discs
same type of potato discs
remove the skin on potato
same number of discs used in each solution
same volume of sucrose
same temperature

Question 2

how can you establish the water potential of potato from data?

Answer 2

when the change in mass is 0, the water potential of solution is same as the water potential of potato

use known values of water potential to find water potential of sucrose solution

Question 3

how could you reduce the uncertainty in data?

Answer 3

use more precise equipment

Question 4

why is % change in mass used in data?

Answer 4

easier to compare sets of data

many of the samples may not have the same starting mass

Question 5

why might the % change in mass be greater than expected in the results?

Answer 5

the sample may not have been dried properly

has more standing water which contributes to increased weight

Question 6

what factors need to be controlled when using cut discs of vegetables in a practical investigating osmosis?

Answer 6

discs need to be the same size
discs need to have the same thickness
same type of vegetable used
same number of discs used
volume of solution
constant temperature

Question 7

why do discs need to be the same size?

Answer 7

ensured that their surface area is equal so does not effect the osmosis results

Question 8

how can you ensure the size of discs are the same?

Answer 8

use a ruler to measure length

Question 9

how can temperature be controlled?

Answer 9

use a water bath

Question 10

what variable goes in the x-axis?

Answer 10

independent

Question 11

what variable goes in the y-axis?

Answer 11

dependent