Molarity Mixup Lab

Connor Delaney

12/12/16

Part I

The findings of this lab yielded results as follows: The yellow solution is the 1 Molar solution, the red solution is the .8 Molar solution, the purple solution is the .6 Molar solution, the blue solution is the .4 molar solution, the orange solution is the .2 Molar solution, and the green solution is the 0 Molar solution. In this experiment we placed different colored bags of dialysis tubing into different colored solutions. For example the yellow solution may have had a red dialysis tubing bag in it. The bags of dialysis tubing were weighed before they were placed in the solutions and after they had been in the solutions for twenty four hours. Using deductive reasoning from which solutions were more concentrated than others (determined by whether the bags gained or lost weight) the results were determined.

    Water will always flow from an area of high concentration to an area of low concentration. This means that when the two different solutions interacted with each other, the solution with the higher concentration of water would be the one to lose weight, and the solution with the lower concentration of water would be the one to gain weight. The solution with the highest molar concentration would also be the solution with the lowest concentration of water. Weighing these bags before and after allowed for the deductive reasoning of which solution between the bag and the solution it was placed in was more concentrated. This led us to conclude that yellow > red> purple> blue> orange> green as far as concentration.

Part II

    For part two of the molarity mixup lab, we set out to calculate the water potential of a parsnip. To do this we placed pieces of parsnip into the different solutions (1 Molar to 0 Molar in increments of .2 Molar). The parsnip pieces were measured for their weight in grams before and after soaking 24 hours with one in each solution. Their percent change in mass was calculated and graphed, in order to determine the molarity of the the parsnip.

Parsnip Samples of Each Molarity Solution Initial Weight (g) Final Weight (g) percent change in mass.

Using the equation of this graph’s trendline, it can be determined that the molarity of the parsnip is around 1.78 Molars. This is when the percent change would reach 0, meaning that the parsnip and solution would have the same molarity at 1.78 Molars. This number can then be used to calculate the water potential of this parsnip using the equation -iCRT. This comes out to -43.64 bars in water potential for the parsnip.