# Ap Bio- Lab 1: Osmosis and Diffusion

Topics: Osmosis, Concentration, Chemistry Pages: 2 (693 words) Published: April 22, 2013
AP Biology
16 April 2013
Lab 1: Osmosis and Diffusion
The purpose of this experiment is to decide which flasks correspond to the solute concentration of sucrose, which are 0.8M, 0.6M, 0.4M, 0.8M. This can be determined by the usage of potato cores. If a potato core’s mass decreases after a day soaked in the sucrose solution, then that flask will have a high concentration of sucrose.

A) The first step in this lab would be cut out four cores of a potato and measure the masses of each individual potato piece. The mass of the potato core would be a variable factor in this experiment. A way that this variable can be manipulated would be each group would be assigned to a specific potato core mass. A controlled variable in this lab would be to pour a certain amount of sucrose solution from a flask into a breaker. An example would be pour 200ML from flask A into a beaker labeled A, 200ML from flask B into a beaker labeled B, and etc. Next, put 1 potato core in each beaker: A, B, C, and D. Leave the cores in the flasks for a day. After leaving the potato cores to soak in the solutions for a whole day, take out the potato cores. Measure the final mass of each potato core and record this data. Afterwards, calculate the percent change in mass. To calculate the percent change in mass, use this formula: [(mass initial - mass final) / (mass initial) ] x 100%. Measure the data results of the percent change of mass in grams. To show a visual picture of the percent change in mass, graph it. This will help in seeing the sucrose molarity among the solutions. To finish, share data with other groups and compare results among one another to obtain an average of all of the results. This will verify that the results acquired were incorrect or correct.

B) My hypothesis was that if a potato core’s mass decreases after a day soaked in the sucrose solution, then that flask will have a high concentration of sucrose. Due to this, I would expect that the potato cores in the 0.4M,...