Saturated steam at a gauge pressure of 2.0 bar is to be used to heat a stream of ethane. The ethane enters a heat exchanger at 16 C and 1.5 bar gauge at a rate of 795 m^3 /min and is heated at constant pressure to 93 C. The steam condenses and leaves the exchanger as a liquid at 27 C. The specific enthalpy of ethane at the given pressure is 941 kJ/kg at 16 C and 1073 kJ/kg at 93 C.   a) How much energy (kW) must be transferred to the ethane to heat it from 16 C to 93 C?   b) Assuming that the energy transferred from the steam goes to heat the ethane, at what rate in m^3 /s must steam be supplied to the exchanger?
I know the answers are a) Q = 5.47×10^3 kW (b) V= 1.27 m^3/s but I don't know how to get those answers. Please use the energy balance equation for an open system: