Diffusion, Dialysis Essay

In Diffusion, Dialysis And 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 10% sucrose, Tube 3 has 20% sucrose, Tube 4 has 30% sucrose, and Tube 5 has distilled water. Tie the tubes and weigh each of them before placing them in there respected beakers. Every 15 minutes weigh the tubes to record the change. In Part B we found that outside test tube; salt existed and not sugar. But inside the test tubes both the starch and the salt existed in the two different tubes. In this part there weren’t any problems and we were successful in gathering the necessary results to move to the next section. This helping prove our hypothesis right because it meant that there would be more changes inside the cell than outside the cell. In Part C we found that Beaker 1 had no changes in weight. In Beaker 2 there were changes that ranged from 0-1. 1. In Beaker 3 there were changes that ranged from 0-2. 1. In Beaker 4 there were changes that ranged from 0-4. 8. In Beaker 5 there were changes that ranged from -2. 7-0. This is the results that my group gathered from another group that did well because our results were way off and inconsistent. So we were forced to use better results to find better explanations. We understood that the conditions under which osmosis is possible and to what degree it occurs. There were three different types of temperate environments. This helping prove our hypothesis right because it meant that different environments help change the appearance of a molecule.