A fluid flows at steady state in and out of a reaction vessel. In the vessel, an impeller imparts work equivalent to 70.0 J/s to the flowing fluid. A heating coil in the vessel adds heat equivalent to 280.0 J/s to the stream. The stream enters the vessel at an average velocity of 7.00 m/s through a pipe with a diameter of D1. The entering stream has a mass flow rate of 0.500 kg/s. The stream exits the vessel through a smaller diameter pipe (D2 = D1/1.5). The two pipes are at the same elevation relative to the ground. The fluid can be considered incompressible, and the temperature change from the beginning to the end of the process is small enough that the change in density can be neglected. Calculate the rate at which the enthalpy of the stream changes.