Problem
A student set out to determine the water potential of potato cells. The initial masses of six groups of potato cores were measured. The potato cores were placed in sucrose solutions of various molarities, and the masses of the potato cores were measured again after 24 hours. She then calculated the percent change in mass, shown in the table below:
|
Molarity of Sucrose in Beaker
|
Potato Core-Percent Change in Mass
|
|
0.0 M
|
17.5
|
|
0.2 M
|
5.0
|
|
0.4 M
|
-7.5
|
|
0.6 M
|
-16.0
|
|
0.8 M
|
-23.5
|
|
1.0 M
|
-24.0
|
A. Describe how the molarity of sucrose affects the mass of the potato core.
B. Describe the difference in mass when the molarity of sucrose is 0.0 M and when it is 1.0 M.
C. The student hypothesized that the mass of the potato cores would increase as the molarity of sucrose increases. Use the data to evaluate this hypothesis.
D. Describe water potential and explain how movement of water molecules across a membrane is affected by concentration gradients.