Calculate the mean repeat unit molar mass for a sample of poly[ethylene-stat-(vinyl acetate)] that comprises 12.9 wt% vinyl acetate repeat units. Given that its number-average molar mass is 39,870 g mol-, calculate the number-average degree of polymerization of the copolymer.

Liquid from a brewery fermentation contains 10% ethanol and 90% water. part of the fermentation product (50,000 kg/h) is pumped to a distillation column on the factory site. under current operating conditions, a distillate of 45% ethanol and 55% water is produced from the top of the column at a rate of one-tenth that of the feed. what is the composition of the waste "bottoms" from the still?