Diffusion, Dialysis & Osmosis Lab

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Introduction

In Diffusion, Dialysis & Osmosis lab, we discovered that we were going to observe and understand the conditions under which diffusion, dialysis, and osmosis occur. Then we constructed models of diffusion, dialysis, and osmosis. We predicted that the direction of change would be from the membrane to the beaker. We understood how these processes affected the selectivity of the cell membrane. The second part of the lab was dealing with dialysis. In this part we studied starch and sodium chloride for dialysis activity. In Part A We hypothesized that NaCl existed in 1-3 and AgNO existed 2-4. In Part B We hypothesized that there will be more changes in the cell then outside the cell. In Part C We hypothesized that there will be a difference due to the different environments that are provide to help change the appearance of a molecule.

Procedure

A. Qualitative testing for sodium chloride and starch
We got 6 clean test tubes and number them 1-6. Test tubes 1&2 had 5ml of 10% sodium chloride (NaCl). Test tubes 3&4 had 5ml of starch. Test tubes 5&6 had 5ml of distilled water. We added 2-3 drops of silver nitrate (AgNO )to 1,3,5. We added 2-3 drops of iodine solution to 2,4,6.

B. Dialysis of a starch/sodium chloride mixture
Get one dialysis tube and tie one end. Fill the bag with 5ml of 10% Sodium chloride solution and 5ml of starch solution from Part A. then tie the tube and place it in a beaker of distilled water. Leave the tube for 30 minutes. Afterwards test for the presence of starch and sodium chloride. Then split the solution into to test tubes and 2-3 drops of iodine into one test tube and 2-3 drops of AgNO in the other test tube.

C. Osmosis using dialysis tubing as a model of the cell membrane Obtain 5 beakers and label them 1-5. Fill beakers 1-4 halfway with distilled water. And beaker 5 with 30% sucrose halfway. Obtain 5 dialysis tubes that will be filled with 10ml of different solutions. Tube 1 has distilled water, Tube 2 has...
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