Diffusion and Osmosis Lab

A couple of class periods ago, our class worked on the osmosis part of a diffusion/osmosis lab. We had to create six "cells" from dialysis tubing that contained 7mL of a different color solution. We already knew what the Molarity of each solution was, we just had to figure out what the "molarity order" was. In order to do this, each "cell" had to be massed. Massing was necessary so we could have an initial mass to figure out the percent change later. We placed each "cell" into a seperate cup filled with distilled water. Distilled water was used because it is pure; It prevents side reactions and contamination of products. If we happen to get an unexpected result, we know it will not be because of the water. After 30 minutes, we went back and remassed the "cells." Now that we had the initial and the after mass, we could find the percent change. With this, we were able to determine the "molarity order."

In between those 30 minutes that we had during the osmosis experiment above, we were able to begin a new experiment involving potatoes. Our goal was to find the solute percent of a russet potato. We began by cutting about 24 pieces of russet potato and then massed the pieces four at a time. Similar to the other experiment, we massed the potatoes now to have an initial mass to figure out the percent change later. We then placed each group of four pieces into cups (six) and put 25 mL of each color solution into each cup. After a few hours, we massed the potatoes again and then figured out the percent change, or the solute concentration.