and outside the dialysis tubing with Benedict’s solution‚ Iodine reagent and silver nitrate solution to find out what has remained in the dialysis tubing‚ and which solutes have diffused through the semi permeable membrane and into the dialysate. Hypothesis: The sodium chloride will definitely pass through the semi permeable membrane because it is a very small molecule‚ compared to the large pores in dialysis tubing. Glucose and starch have bigger molecules‚ and therefore are less likely to pass
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to each tube and heated both tubes together in the (~95°C) water bath for two minutes. Then‚ recorded the results in table 1. 2. Added a few drops of fresh solution A and B separately spaced on a white tile. On each solution‚ added 1-2 drops of iodine solution and mixed with pen cover. Recorded your observations in the table 1. 3. Pipetted 2 ml solution B into each of four boiling tubes. The tubes were labelled 1‚ 2‚ 3 and 4 respectively near mouth of tube. Labelled your group name. 4.
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Vitamin C: freshly squeezed OJ‚ bottled OJ‚ frozen OJ‚ canned OJ * Optional: container for waste solutions and source of clean rinse water There are two different preparations (starch-iodine or indophenol) that may be used for the vitamin C indicator solution. Neither is more accurate than the other. The starch-iodine mixture is much cheaper. It can be made ahead and stored in a dark‚ cool place in two liter soda bottles and dispensed in liter containers at the lab stations. Both indicators vary
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reaction so that less ATP is produced. Hypothesis: There is an inverse relationship between the mass of lead nitrate and the ability of amylase to convert starch into maltose. Variables: Independent Variable: The mass of lead nitrate dissolved in each of the solutions. Dependent Variable: The change in the color intensity of the iodine. Controlled variable: Time: the reaction was allowed to proceed for twenty minutes. Temperature: the water bath was set at 40˚C. This was to provide
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solution glucose test strip 1% starch solution distilled water Lugol’s iodine solution Procedure: Each member of the lab group will complete the procedures independently 1. Obtain a 30 cm piece of 2.5-cm dialysis tubing that has been soaking in water. Tie off one end of the tubing to form a bag. To open the other end of the bag‚ rub the end between your fingers until the edges separate. 2. Place 15 mL of the 15% glucose/1% starch solution in the bag. Tie off the other end
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concentration of the ascorbic acid in the tablet‚ a redox reaction of it with iodine was done. While iodine is an oxidizing agent and ascorbic acid is a reducing agent. The reaction forms dehydroascorbic acid and iodide. Ascorbic acid + I2 -> dehydroascorbic acid + 2 H+ + 2 I- However‚ Iodine does not dissolve in water very well. In this case‚ standard solution of potassium iodate(V) is used to produce aqueous iodine. Excess potassium iodide and dilute sulphuric acid is added to react with potassium
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dialysis bag as a model of the cell membrane. Our hypothesis was that the glucose will diffuse out of the membrane into the beaker filled with iodine solution. To demonstrate dialysis tubing we used water‚ starch and iodine. When starch and iodine react together they form a dark brown color. Materials Rubber band Dialysis bag Beaker Glucose solution Iodine solution Water‚ thread Methods Cut a piece of dialysis tubing that has been soaking in water approximately 40 cm (approx. 16 in) long
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DISCUSSION Considered as moderately weak oxidizing agent‚ Iodine was used for the determination of strong reductants. Standard iodine solutions were found to have smaller electrode potentials as compared with the other oxidants‚ gaining them the advantage of imparting a degree of selectivity essential in the determination of strong reducing agents amid the presence of weak agents. Although regular re-standardization was essential for Iodine solution due to its lack of stability‚ it was still suitable
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teacher’s instructions for handling the solutions. Wear eye protection when handling the iodine solution. Investigation * Place single drops of iodine solution in rows on the tile. * Label a test tube with the pH to be tested. * Use the syringe to place 2 cm3 of amylase into the test tube. * Add 1 cm3 of buffer solution to the test tube using a syringe. * Use another syringe to add 2 cm3 of starch to the amylase/ buffer solution. Start the stop clock and leave it on throughout the
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reaction occurs; - the iodate ions are reduced to form iodine Burette containing potassium iodate solution IO3− + 6 H+ + 5 e− → ½ I2 + 3 H2O - while the iodide ions are oxidised to form iodine. 2 I− → I2 + 2 e− Combining these half-equations demonstrates the reaction between iodate and iodide 2 IO3− + 10 I− + 12 H+ → 6 I2 + 6 H2O It is the iodine formed by this reaction that oxidises the ascorbic acid to dehydroascorbic acid as the iodine is reduced to iodide ions. ascorbic acid + I2 →
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