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3. A chemist dissolved a 5-40-g sample polymer in a solvent. He added nonsolvent gradually and precipitated out successive polymer-rich phases which he separated and freed of solvent. Each such specimen (which is called a fraction) was weighed, and its number average molecular weight M, was determined by membrane osmometry in a suitable solvent. Following are his results. Fraction no. Weight (8) M. 2,000 50.000 22.0 100,000 12.0 200.000 4.5 500,000 1.5 1.000.000 Assume that each fraction is monodisperse, calculate M. Mw and a measure of the breadth of the number distribution for the recovered polymer. 1.5 5.5