I am currently working on a lab report and am confused by the questions involved

Question

I am currently working on a lab report and am confused by the questions involved:

I have already done both of the graphs in the titration, shown by the following 2 graphs, labeled which is which at the top:

With the questions, I assumed that the MW was given for Glycine, at 75.0666? And I am not sure how I am supposed to determine the MW of the unknown without knowing the identity, which I assumed I would just find from the pK values? But I'm having a hard time deciding between a few of them. What would be my rational for selecting one of these amino acids other than just good guessing? Any help is appreciated!

(1) Plot two pH titration graphs (computer generated, one for glycine, one for the unknown); mark the pKas on each graph. (2) Calculate the molecular weight for glycine from the titration curve. Show your work. (3) Calculate the molecular weight for the unknown from the titration curve. Show your work.

Explanation / Answer

.2.) Consider the end point of the reaction ,which occur at PH=7, and find the corresponding volume of NaOH used from the graph. .

With known normality of NaOH(N1) and its volume(V1) and known volume of glycerine (V2) which you took we can find the normality of glycerine (N2). by using following formulae.

N1V1 = N2V2 find N2  with N2 find molecular weight of glycerine using,

N2 = (W/ GMW) / volume.

3.) the same can be done for the unknown solution to obtain the its MW.

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