An open tank, 3.0 m in diameter, contains liquid benzene at 37°C exposed to air also at 37°C and 1 atm absolute pressure. Assume that the rate of evaporation is controlled by diffusion through a stagnant gaseous film, 0.50 cm thick, adjacent to the benzene surface. The mole fraction of benzene outside this film is zero. Determine the rate at which the benzene evaporates in kg per day and the rate at which the liquid level changes in m/day. Suggest some ways in which the loss of benzene from the tank could be mitigated.