For polymerization of styrene in tetrahydrofuran at 25°C using sodium naphthlide as initiator, the rate coefficient for propagation is 550 dm3 mol-1 s-1 . If the initial mass concentration of styrene is 156 g/dm3 and that of sodium naphthalide is 3.02 x 10-2 g/dm3 , calculate the initial rate of polymerization and, for complete conversion of the styrene, the number average molar mass of polystyrene formed. Calculate, and comment upon, the value of the molar mass dispersity (Mw/Mn).