Boiler Steam Propblem Thermodynamics?

Steam leaves a boiler at 600 deg F and a pressure of 150 psia. Find the following properties for this steam Internal energy, u, btu/lbm Specific volume,v, cubic feet/lbm Enthalpy, h, btu/lbm Entropy, s, btu/lbmR. If this steam is allowed to enter a turbine where energy is extracted in the form of mechanical energy (it spins the turbine!) and its pressure drops to 15 psia but its entropy stays at 1.7110 btu/lbmR (this is called an isentropic expansion), what is the state (condition) of the steam?