a$)$ Oxygen at $230$ K and $21\mathrm{.}25$ atm has a tabulated specific volume of $3\mathrm{.}87$ cm$3/$g and a specific internal energy of $3450$ J$/$mol$.$ Calculate the specific enthalpy of Oxygen in this state.

b$)$ Air is heated from $25$ C to $150$ C prior to entering a reactor. The change in specific enthalpy associated with this process is $4250$ J$/$mol$.$ The flow rate of air at the heater outlet is $6\mathrm{.}25$ m$3/$min and the air pressure at this point is $122$ kPa absolute$.$ Calculate the heat requirement in kW$,$ assuming ideal gas behavior and that kinetic and potential energy changes from the heater inlet to the outlet are negligible.