Natural gas having a molar analys s o 60% methane CH4 and 40 ethane C2H6 enters a com pressor at 340 K 6 bar and is compressed sot er irreversibilities to 20 bar. The compressor operates at steady state, and kinetic and potential energy effects are negligible. ally without internal (a) Assuming ideal gas behavior, determine for the compressor the work and heat transfer, each in kJ per kmol of mixture flowing (b) Assuming ideal solution behavior, determine for the compressor the work and heat transfer, each in kJ per kmol of mixture flowing For the pure components at 340 K 20 bar Methane715.33 704.400.9763 0.3275 73493 6.9680 6 bar 20 bar6bar Ethane 46239 439.13

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Heat is added to a piston-cylinder device filled with 2 kg of air to raise its temperature 400 c from an initial temperature of t1 27 cand pressure of pi 1 mpa. the process is isobaric process. find a)-the final pressure p2 b)-the heat transfer to the air.

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.