Affects of Osmosis and Diffusion
Perfume spreads in a room, hands bloat when left in water for too long (shriveling is a common misconception), a tea bag’s contents diffuse through the water. These are all examples of diffusion and osmosis. These phenomena happen everyday and people don’t realize what is actually happening. The purpose of the lab is to see the effects of diffusion and osmosis. In part B, the higher the concentration of solute, the higher the mass of the solution. Methods and Materials:
For part A of the experiment, the following items are needed: Dialysis tubing, IKI solution, 15% glucose/1% starch solution, distilled water, balance, sucrose solutions (0.2M, 0.4M, 0.6M, 0.8M, 1.0M), glucose test tape, beakers (multiple), petri dish. In the experiment, one will measure diffusion through a selectively permeable membrane (dialysis tubing). A 30 cm by 2.5 cm piece of dialysis tubing that has been soaked in water is acquired and made into a bag by tying one end of the dialysis tubing and opening the other end. Next, place 15 mL of the 15% glucose/1% starch solution into the dialysis tubing. After this step, tie off the end that is still open and effectively turn it into a model of a cell (for the purpose of this lab). Afterward, fill a beaker with 250 mL of distilled water but bake sure that the beaker is either three-fourths full. 4 mL of IKI should be added to the beaker and the color should be recorded. In order to check for contamination, perform the Benedict’s test on the water and measure with glucose tape. Next, in order to place the dialysis tubing into the beaker, rinse the tubing with distilled water and make sure that there are no leaks or tears in the bag. Slowly place the bag into the beaker and make sure the tubing is completely submerged. Allow the bag to stay in the water for 30 minutes unless a color change is observed in the bag or the beaker. Finally, test the liquid in...
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