1. The viscosities of a series of solutions of polystyrene in toluene were measured at 25C and the results obtained are summarized below in Table 1. Determine the molecular weight of this polymer? The Mark-Houwink-Sakurada constants for this system are K=4.5104Lg1 and a=0.5. Table 1. Viscosity measurements obtained for a series of polystyrene solutions in toluene []=kMnsq=(0)/0 2. 15g of polyurethane containing two isocyanate (NCO) end-groups was titrated with 0.2M(M=mol/L) n-butyl amine and required 13.17mL to reach the end-point. What is the number average molecular weight of polyurethane? (Mbutyaminc=73.14g/mol)