lab report 5

Module 5 Lab 5 Osmosis
Purpose
This lab will demonstrate how water moves across a semipermeable membrane in solutions of differing tonicity.
Hypothesis
If a “cell” is placed in a hypertonic solution then its mass will be lower by the end of the experiment; if a “cell” is placed in an isotonic solution then its mass will remain the same by the end of the experiment; if a “cell” is placed in a hypotonic solution then its mass will be greater at the end of the experiment.
Materials:
scale or balance
24″ dialysis tubing
4 transfer pipets
sugar
scissors
rubber bands
four coffee cups – they need to be roughly the same size
250ml graduated cylinder
ruler
small sauce pan
3 clean containers (600mls (about 20 ozs) or larger)Methods:
1. Cut four 6-inch pieces of dialysis tubing and soak in a coffee cup filled with tap water for 2 hours prior to your start time. While waiting, prepare the sugar solutions using the following protocol: you will need a saucepan, tap water and sugar near the stove for this portion of your experiment. Prepare the following three solutions:
A) Add 5 grams of sugar to your 250ml graduated cylinder and then add water up to the 250ml mark. You will place a small piece of plastic wrap over the top of the graduated cylinder (or parafilm if you have that), and mix the sugar with the water. Then pour the contents into a small saucepan over the stove. You will fill the graduated cylinder up to the 250ml mark again and then pour the tap water into the saucepan as well. You will now heat the mixture on the stove and stir until the sugar has dissolved. Once this has happened, you will remove the solution from the saucepan, pour the solution into a container and label that container 1% sugar solution.
B) Rinse the saucepan and then add 100 grams of sugar to your 250ml graduated cylinder and then add water up to the 250ml mark. You will place a small piece of plastic wrap over the top of the graduated cylinder (or parafilm if you have…