Air flows steadily from a tank, through a hose of diameter d 0.03 m, and exits to the atmosphere from a nozzle of diameter d 0.01 m. the pressure in the tank remains constant at 3.0 kpa (gage), and the atmospheric conditions are standard temperature and pressure. determine (a) the flowrate and (b) the pressure in the hose.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.