Diffusion And Osmosis

This data was analyzed by calculating the cumulative change in weight for each dialysis bag. This was done from subtracting the weight of each bag from the initial weight of the bag. Doing so, allows the weight of each bag to be initially zero. For that, we must calculate the corrected cumulative change in weight. For each time interval of 10 minutes, we subtracted the change in weigh of bag #1 (tap water) from the weight of each bag at the specific time measure- this corrected any oscillations.

The dialysis membrane’s permeability was tested with four substances. Starch, sulfate ion, chloride ion, and albumin are all substances of different sizes. Albumin is a protein that is fairly large so it cannot diffuse through a semi-permeable membrane. Ions such as the sulfate and chloride ion are small enough that they can go through the microscopic pores of the dialysis tubing.

Using the graduated cylinder, measure 20mLs of the stock sucrose solution and 180mL of water to create a 3% sucrose solution and place it into the 250mL beaker (beaker #2). Place bags #1‐3 (red, blue, yellow) into beaker 2 and bag #4 (green) into beaker 1. Allow the bags to sit for one hour. After allowing the bags to sit for one hour, remove them from the beakers carefully open the bags, noting that often times the tops may need to be cut as they tend to dry out. Measure the solution volumes of each dialysis bag using the empty 250 ml beaker.

Random movement of solute (dissolved particles) and solvent (water molecules) will result in an evenly distributed solution.

We filled bags of dialysis tubing with 20 ml of sucrose, NaCl, ovalbumin, and glucose and weighted them. After soaking them in distilled water for 10 minutes we measured them again. All of the bags gained water. Our hypothesis was that water will diffuse into the cells with ovalbumin, NaCl, glucose, and sucrose, but not the bag with distilled water. The independent variables were the different solutes in the dialysis tubing. The dependent variable was if the water would diffuse into the

The purpose of this experiment was to test the effects of various solute concentrations on rate of osmosis in dialysis bags. The hypothesis was that the rate of osmosis would increase as solute concentration increase. Bag 1 was the only isotonic bag, due to the water flowing evenly inside and outside of the bag. Bags 2-4 were hypotonic and were exposed to a hypotonic environment causing the water to flow inside the bag, where there were more solutes. The water moved inside the bag to try to balance the solute concentration on both sides of the membrane. Figure 1, shows that bag 4 had a higher rate of osmosis due to having a higher solute concentration of 60% sucrose compared to bag 2 with a sucrose concentration of 20%. Which supported the

Simple Diffusion: Movement of molecules from one location to another solely as a result of their random thermal motion

Then 50 ml beaker with the glucose and starch mixture was also tested for glucose with a glucose strip. The dialysis tube was then clipped on one end and opened on the other end. The 15 ml of glucose and starch mixture was then poured into the dialysis tube with a pipette. The dialysis tube was then twisted and clipped on the unclipped end of the tube. The mass of the tube was then measured by a quadruple beam balance. The tube was then rinsed in the sink and blotted dry by a paper towel to clean the tube in case some of the glucose accidentally spilled out of the tube. The tube was then placed into the 250 ml beaker and left there to sit for 15 minutes. After 15 minutes, the 250 ml beaker was then tested for glucose with a glucose test strip and so was the contents inside of the tube. All observations and results were recorded in the chart below the procedure. Such observations listed were things like color change in the solutions, mass changes in the dialysis tubing, and what the glucose strips would indicate about the solution

The experiment has been conducted previously yielding various results. External factors affecting the rate of diffusion play a part in this experiment. Heat due to its influence on the thermodynamics of the molecular substances. Increasing

The diffusion lab required the class to explore the concept of diffusion, using dialysis tubing as a model of a selectively permeable membrane. We were able to observe the random kinetic energy of glucose, IKI, and water molecules through the dialysis tubing as the molecules moved themselves between the solutions in the beaker and the dialysis bag. After 30 minutes, the solution in the beaker tested positive for the presence of glucose, proving that the glucose molecules had diffused from the bag to the beaker. The IKI solution must have also diffused across the membrane because although initially only the solution in the beaker contained IKI, the solution within the dialysis bag turned purple-black by the end of 30 minutes, indicating that

Hypothesis: When observing molecule size in relation to diffusion rate, we expect smaller particles to farther along the agar because the size of a particle and rate at which it diffuses correlates negatively. In the osmosis and dialysis experiment, water should move down its concentration gradient. The sucrose dialysis bag is hypertonic compared the DI water, so it will gain volume; and, the dialysis bag containing DI water is hypotonic compared to the sucrose solution of the beaker, so the bag will lose volume. Lastly, because Iodine

Introduction: In nature, molecules are always in motion. When molecules move from high concentration to a low concentration across the membrane, this is called diffusion. In other words, when particles go down the concentration gradient, also called passive transport. A special type of diffusion is also called osmosis, which is the diffusion of water, meaning water particles (H2O) move from high concentration of water particles to a low concentration through a selectively permeable membrane. Higher water concentration can also be phrased as higher water potential.

The purpose of this experiment was to examine the permeability of the dialysis tubing using molecules of various sizes (iodine, water, glucose, and starch) and reagents to help identify the molecules in the solution. It was assumed that iodine, then water, followed by glucose and starch respectively, would have the most ease of movement, as they are in the order of size (least to greatest). Being an element, iodine is the most minuscule out of the four, as they are the building blocks for molecules, such as: water (H2O). As a result, iodine was able to move with ease through the dialysis tube from the beaker with water, which was indicated by the tints of black and purple in the dialysis tube, as a result of the reaction between this element and starch. Consisting of molecular compounds, carbohydrates are created with the three elements, carbon, hydrogen, and oxygen in a one to two to one ratio.

When the different dialysis tubes with different substances were placed in water, diffusion took place; this is when the particles moved from a high concentration region to a low concentration region. Osmosis is the act of moving through a semipermeable membrane. Therefore the lab required a semipermeable membrane; however a semipermeable membrane is only found in cells so students used dialysis tubes. The dialysis tubes used, allowed the substance within to flow outside of the tube, essentially working as a semipermeable membrane. The osmolarity for the substances were different, the osmolarity can be determined by the amount of solute particles in a liter or per liter. In the lab there was one isotonic solution this was the blue solution. The mixture was isotonic because both the solution outside of the tube and inside of the tube had the same amount of concentration. During this lab both hypotonic and hypertonic solutions were observed. Hypotonic is when the osmotic pressure is lower than the fluid. Hypertonic is when the osmotic pressure is higher than the fluid. The students were able to observe this with the different color

The dialysis tubing, pre-soaked in water, was tied at one end to form a water tight seal. After opening the other end of the tube, 2 droppers of the starch solution and 2 droppers of the glucose solution were placed inside, before being tied off on the other end. The “cell” was weighed to determine its density before the experiment was conducted. Distilled water was measured out into a 150mL beaker and the “cell” is placed inside. 10 drops of iodine were added to the distilled water, and the contents of the beaker became visibly yellow. The beaker was moved aside and monitored for 30 minutes. After 30 minutes, the “cell” was removed from the liquid, dried with a paper towel, and weighed again. By weighing again, it was determined whether or not any substances had moved in or out of the artificial plasma