Osmosis Practical

Question 1

how is a calibration curve used to find the concentration of plant tissue?

Answer 1

plot a calibration curve of percentage change in mass against concentration

find x intercept where the plant tissue is isotonic to the sugar solution.

Question 2

what is the purpose of calibration curves?

Answer 2

used to determine the concentration of an unknown sample by comparing it to a set of standard values with known concentrations

Question 3

what occurs when plant tissue is placed in a hypotonic solution?

Answer 3

water moves into the plant tissue by osmosis

plant tissue increases in mass

Question 4

what occurs when plant tissue is placed in a hypertonic solution?

Answer 4

water moves out of the plant by osmosis

plant tissue decreases in mass

Question 5

why are potato cylinders left in solution for 20 minutes?

Answer 5

to allow time for osmosis until the plant reaches equilibrium with its surrounding solution

Question 6

why is percentage change in mass used rather than actual change in mass?

Answer 6

allows for comparison

Question 7

what is indicated by the x-intercept of the calibration curve?

Answer 7

concentration that is isotonic to solution tested

Question 8

why are potato cylinders dabbed dry after removal from the solution?

Answer 8

remove excess water that may interfere with mass

Question 9

what are control variables?

Answer 9

-volume of sugar solution
-size of potato chips
-length of time in solution