ChemE 178 HW7Due Oct31

1.) The following osmotic pressure data was obtained for polystyrene in toluene at 250C.Concentration (g/cm3 x 103) (cm toluene)2.56 0.3253.8 0.5455.38 0.8937.8 1.5788.86 1.856The density of toluene is 0.8618g/cm3 and g=981 cm/s2. a) Calculate the number average molecular weight.b) Calculate the second virial coefficientc) What is the quality of the solvent?d) Will the chain of polymer in dilute toluene solution have a radius of gyration larger, smaller, or the same as the same chain of this polymer in melt? Why?

2.) Y&L problem 3.11

3.) Six poly(methyl methacrylate (PMMA) standards of varying molecular weights with polydispersities of < 1.1 were synthesized. Below are their intrinsic viscosity data determined from solutions of these polymers in benzene at 250C. Determine their Mark-Howink-Sakurada constants, K and a.

Molecular weight (g/mol) (dL/g)46000 0.25882000 0.408152000 0.663253000 10.893348000 1.226856000 2.210