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... Another reason for this variability could be due to the unequal distribution of KMnO4 solution because of insufficient stirring. ... If the solution was more thoroughly stirred the error variable would be lower, however carelessness could also lead to change in the diffusion rate by the touching or moving of the permeable 田ell・ Variability is also directly caused by the spectrophotometer after . ...
Figure 2, which was derived from figure 1 by taking 2 minute intervals at various places along the graph, has a rapidly decreasing rate of diffusion for the first 10 minutes. This gradually levels off and becomes constant reaching close to zero diffusion by the end of 75 minutes. ... The variability is slight and is accounted for so the inverse proportion relationship of diffusion rate to time is accepted. ... Though, for figure 3 the data represents the diffusion rate of 3-5 minutes at different temperatures for the whole class. ... Assuming zero diffusion at zero Celsius, because water freezes at 0C, the line that best fits the trend of the points concentrated around the means is an exponential curve. ... One major one is the way the knot was tied after the KMnO4 was put into the cell. The way the knot is tied could contribute to the diffusion as well as the surface area of the 田ell・which also affects the diffusion rate. Also some samples had air in them causing them to float reducing the surface area that was in contact with the water, which also reduces the rate of diffusion. ...
In figure 4 the diffusion rate is compared to molecular weight, and the general trend is a decrease in diffusion rate as molecular weight increases. ... In this data set there are two pairs of samples which have similar molecular weight yet different rates of diffusion. Malachite green and Methylene blue, both between 360-380 Daltons, have similar rates of diffusion. However, Eosin yellow and Congo red which are about 690-700 Daltons have significantly different diffusion rates. ... Another source of error is that the diffusion line is not defined so some estimation is required. ... Thus the inverse proportion between diffusion and molecular weight is accepted.
Approximate Word count = 1761
Approximate Pages = 7
(250 words per page double spaced)
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