Bio lab report osmosis Assignment

Bio lab report osmosis Assignment Words: 1356

It may also be used to describe a physical process in which any solvent moves across a comparable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work. The osmotic pressure is defined to be the minimum pressure required to maintain an equilibrium, with no Nett movement of solvent. Osmotic pressure is a colligating property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.

Osmosis, unlike diffusion, requires a force to work. This force is supplied by the solute’s interaction with the membrane. Solute particles move randomly due to Brownian motion. If they move towards pores in the membrane, they are repelled, and in being repelled, acquire momentum directed away from the membrane. The momentum is rapidly transferred to surrounding water molecules, driving them away from the membrane as well.

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The osmotic gradient is the difference in concentration between two solutions on either side of a comparable membrane, and is used to tell the difference in percentages of the concentration of a specific particle dissolved in a solution. Usually the osmotic gradient s used while comparing solutions that have a comparable membrane between them allowing water to diffuse between the two solutions, toward the hypersonic solution (the solution with the higher concentration).

This would effect the final reading of the percentage of weight change because the cut potato cubes would be having a either a higher mass or lower mass depending whether the potato cube was cut slightly bigger than 1 CM or slightly smaller than lack respectively. The increase in weight for the potato cubes as hon.. In the table for example during trial 1 was different than in trial 2 for the distilled water. This would end up having an average and a less precise reading of the final weight change, hence having a less precise percentage of weight change. The second random error could have possibly been the time to end the stopwatch at exactly fifteen minutes for each and every one potato cube immersed in the salt solution. This would end up in most probably having an excess of salt solution in the potato cube as the chances of having a less salt solution is lower.

This is because the delayed time of reaction after the stopwatch ad shown fifteen minutes may have caused excess salt solution to enter the potato cube causing the final mass of the potato cube to increase more than what it should have been, thus increasing the average weight change of the potato cubes and the percentage change. This was most probably shown in the trial 2 of the 2% salt solution. Hence, the reading of the trial 2 was larger than the reading of the trial 1 of the 2% salt solution. The third random error was that the measuring cylinder used to measure the salt solution of different percentages was washed with distilled water and was not dried properly. This would result n the salt solution being diluted by the distilled water causing the percentage of the salt solution to decrease. This WOUld then effect the results of weight change because the salt solution is then not what it is supposed to be.

It would have been lower than expected and the percentage of weight change of potato cubes would have been lower The last random error that was possible in this experiment was the drying of the potato cube was not constant before and after it was immersed into the salt solution. This would have left the readings to be not the same for every trial of different percentage of salt solution. The tissue paper used was not given the same drying capabilities for each of the potato cubes. Drying capabilities meaning the length the tissue paper was placed on the potato CUbes to absorb the remaining salt solution, the tissue paper was reused and didn’t having the absorbing capabilities of what it should have been having and many more factors.

This would then change the data for each and every trial for different percentages leaving the mass obtained to not be precise, hence, causing the percentage of weight change to be different for each and every trial and this would effect the precision of the experiment. Some of the Seibel systematic errors in this experiment are the temperature of the room was kept at a cold temperature with the air-conditioning. This would effect the rate of which the the water diffuses to the potato cubes from the salt solution to potato cubes or the potato cubes to salt solution. The final percentage of weight change would be effected as well as the average weight change of the of the potato CUbes.

This is because the osmosis process may have been slowed down because of the rate of water diffusion decrease which would decrease all the readings of the final weight of the potato cubes Lastly, the final systematic error is that the salt solution used for all were not washed correctly down to its percentage. For example, the original stock of salt solution given to the lab was 5% and the one that was washed down was not exactly to 0. 5%, and 3%. The readings could be higher or lower depending on the way the original salt solution was washed. This means that the reading of the percentage of weight change would change in all directions because the 1% of the salt solution could have been 2% and the reading would have increased causing the average weight change to increase and the percentage of the weight change to increase. Some f the strengths in this experiment is the use of a digital stopwatch to measure the time taken.

This helps a lot because the time taking would be easier and it would have reduced the chances of having a random error. Another strength is use a peeler to peel the potato skin off before cutting it. This helps by not wasting time and having the chance of cutting ourselves using a knife. Some of the weakness of this experiment is the environment where the experiment was done. There was presence of air molecules blowing from the air-conditioning and this would have maybe dried the potato cubes that came out of the salt solutions quicker than what it should have. The ways to improve this experiment is based on the weakness which is to turn off the air-conditioning during the experiment.

This would help drastically because there will be no external air forces drying the potato cubes faster than what it should be because blowing air is a factor that effects rate of loss of water. The significance of this experiment is to show that the water moves from a higher concentration gradient to a lower concentration gradient and that the salt solution depending on the percentage would effect the mass of the potato cubes because the salt solution either moved into the potato bubs or the water in the potato cubes moved out and into the salt solution. This is also to show that cells do osmosis to regulate the osmotic pressure in themselves and they do this on a regular basis to maintain the turgidity of the cell.

Cell to cell diffusion of water is controlled by this process called osmosis. Some of the precautions that were taken in this experiment was the usage of lab coats all the time during the experiment. This is to ensure that even a harmless solution like a salt solution wouldn’t come in contact with our skin or dirty our clothing. The knife was used carefully because it was sharp and so that no cuts were gotten on our fingers. All the apparatus and material were handled with care so that we do not break them. Overall, this experiment was a success. My lab partner, Elian and I managed to work together well to accomplish this experiment successfully. This included us splitting the task equally.