Question

In: Chemistry

Calculate Mn & Mw, and the polydispersity index (PI) for the molecular weight data provided below...

Calculate Mn & Mw, and the polydispersity index (PI) for the molecular weight data provided below and graph. Repeat your calculations if the molecular weight data were changed by increasing the frequency (# of chains) of the following molecular weights by 500 for molecular weights of 600, 700, 800, 900, 1000, and 1100 and graph. Explain what happens to the PI and what this means in terms of molecular weight distribution. Input data and graph in Excel or similar graphing program and dropbox your Excel file (both graphs along with the Mw, Mn, and PI for each each data set).

Mi (g/mol)	Ni	Mi (g/mol)	Ni
50	1100	900	6300
100	1300	1000	5200
200	1600	1100	4100
300	2000	1200	3300
400	2600	1300	2500
500	3300	1400	1900
600	4100	1500	1600
700	5200	1600	1300
800	6800	1700	1100

Expert Solution

The number-average molecular weight (M_n) for the given data =

M_n= 848.7

the weight-average molecular weight = M_w =

New Mn value after caertain addition in the molecular weights =

M_n= 1135.3

M_w=

PI=1.16

The decrease in the PDI indicates decrease in the number of branches and increase in the monodispesity

queen_honey_blossom answered 2 years ago

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