A pipe of length 400 m is used to pump H2 from a vessel maintained at 25 barg to a second vessel at 20 barg. The H2 is at 25 o C and its flow rate is 0.2 kg/s. If isothermal conditions are assumed and the friction factor f can be assumed to be 0.005 what is the diameter of the pipe? Hint: Use E balance 2 21 2 211 + 2 ( 1 2 + 2 ) = 0