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1 kg air in a piston-cylinder assembly is heated at constant pressure, resulting the expansion of the volume. The initial temperature of the air was 300 K, and the air temperature becomes 500 K after the expansion. What is the boundary work done by the air? Assume that air is an ideal gas with constant specific heats ( 0.718 v c = kJ/kg-K and 1.005 p c = kJ/kg-K)..

Respuesta :

MechEngineer

Answer:

201 kJ

Explanation:

Using the law of energy conservation in thermodynamics, the boundary work done by the air would be the same as the heat energy supplied to the air it self.

[tex]E = mc\Delta T[/tex]

where m = 1 is the mass of air, c = pc = 1.005 kJ/kgK is the specific heat in a pressure controlled environment. ΔT = 500 - 300 = 200 is the change of temperature

[tex]E = 1*1.005*200 = 201 kJ[/tex]