Rate Of Diffusion Lab Report

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The Effect of the Molecular Weight of a Substance to its Rate of Diffusion Paulo E. Garcia Group 2 Sec U-7L October 16, 2014 ABSTRACT The rate of diffusion was tested by using a petri dish with agar-water gel and three drops of different solutions. These solutions were observed for thirty minutes and measured every three minutes. The different solutions used are Potassium permanganate with a molecular weight of 158 g/mole diffused the greatest distance among the three, Potassium dichromate with a molecular weight of 294 g/mole diffused the lesser than that of Potassium permanganate, and Methylene Blue with a molecular weight of 374 g/mole diffused the least distance. Therefore, the lower the molecular weight of a substance,…show more content…
One drop of each substance was carefully placed into each well. After all wells were filled with its corresponding substance, the petri dish was immediately covered and the diameter of each solution was measured using a ruler. The initial measurement was recorded as the measurement for zero minute. Every three minutes, the sizes of the diameters were measured and entered in a table until the thirtieth minute. The values in the table were plotted using a line graph to see the differences in the rate of diffusion among the three prepared solutions. Then, the partial rate of diffusion for each value was calculated by dividing the difference of the diameter of colored area at a given time (di)and the diameter of colored area immediately before di divided by the difference of the time when di was measured (ti) and the time immediately before (ti). The averages of the computed partial rates of each substance were their average rates of diffusion that were plotted on a bar graph to observe a clearer relationship between the…show more content…
The molecular weight of a substance has a great influence to its rate of diffusion. The results from the experiment showed that a substance with a lower molecular weight like potassium permanganate has a high rate of diffusion unlike other substances with high molecular weight because of the number of diffusible molecules. If there is a high quantity of diffusible molecules present in a substance, most likely, it will have a slow rate of diffusion. More accurate results can be achieved by considering various factors like the correct handling of specimens, the type of medium where diffusion is taking place, temperature, equal amount of substance used, and others. LITERATURE CITED Brown, LeMay, Bursten. 2005. Chemistry: The Central Science. 10th ed. New Jersey: Pearson Prentice Hall.p.426. M.Hein, S. Arena. 2011. Foundations of College Chemistry. 13th ed. New Jersey: John Wiley & Sons,

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