A rigid tank of volume 2.3 m3 contains air at 0.21 bar, 290 K. A leak develops and air flows in slowly from the surroundings, which are at 1.1 bar, 312 K. After a while, the tank and its surroundings come to equilibrium. Neglect kinetic and potential energy effects, and assume the air is an ideal gas with constant specific heats evaluated at 300 K.

a. What is the final temperature in the tank, in °C?
b. How much mass has entered the tank, in kg?
c. What is the amount of energy transfer by heat for a control volume that encloses the tank, in kJ?

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?

What is the major difference between thermoplastics and thermosetting plastics from the polymerization structure point of view?

An electric kettle is made out of stainless steel, weighs two pounds (when empty) and is equipped with a heating element that consumes 2 kw of electricity. assuming that the water and the kettle are at the same uniform temperature at any moment of time, calculate the shortest possible time to bring 2 quarts of water from room temperature to the onset of boiling