A liquid toluene stream at 1 atm and 25 o C needs to be heated and fully converted to a saturated vapor at 1 atm. Medium pressure steam will be used as a heat source. Assume steam enters the heat exchanger as a saturated vapor at 4.0 bar and 143.6 o C, and exits as a saturated liquid at the same pressure. If the toluene flowrate is 350 mol/h, how many kg/h of steam are needed?