6) Researchers also have developed microbial fuel cells that can generate electricity by recovery the chemical energy in the urine. Typically, human urine contains 98% water and 2% urea in weight. The chemical energy that can possibly be recovered is imbedded in urea, and the chemical equation is as follows: aCO(NH2)2+bO2cCO2+dN2+eH2O The energy density of urea is about 600kJ/mol. Assuming that the building can collect urine from 300 people every day, each person contributes 200mL urine on average, the microbial fuel cells have an energy efficiency of 5%, calculate the total electrical energy that can be generated per year. (10 points)