An insulated 8m* rigid tank contains air, modeled as an ideal gas, at 600kpa and 400k. a valve connected to the tank is opened and air is allowed to escape until the pressure drops to 200kpa. the air temperature is held constant during the process by an electric heater placed in the tank. determine the electrical energy supplied to the air during this process. internal energy of the initial air is u = 286.1 6hĺ kg ; the enthalpy of the exiting air is hvit400.98hj/ kg

Explanation:

We assumes that all the electrical energy produced will be converted into the heat energy.

    Electrical energy input = Heat energy absorbed by object = Heat energy required = Q

As,        Q = U - W

                = U - RT

Since, it is given that U = 286.1 kJ/kg, is 600 kPa, is 200 kPa, and T is 400 K.

Therefore, putting these given values into the above formula is as follows.

          Q = U - RT

              =

              =

              = 412.27 kJ/kg

Thus, we can conclude that the electrical energy supplied to air is 412.27 kJ/kg.

to make a supersaturated solution, make a saturated solution of sugar by adding 360 grams of sugar to 100 ml of water at 80 degrees celsius. when the water cools back down to 25 degrees, that 360 grams of sugar will still be dissolved even though the water should only dissolve 210 grams of sugar.

zfoods? ok, pressure is used to keep the heat inside and to keep the food perfect.