Please show some work if you expect to recieve the points: The volume of 1 kg of
ID: 787173 • Letter: P
Question
Please show some work if you expect to recieve the points:
The volume of 1 kg of argon (MW = 40) in a closed piston-cylinder device is initially 0.5 m3. Now the gas is expanded at a constant pressure of 150 kPa to a volume of 1.3 m3. What is the initial temperature (degree C)? What is the final temperature (degree C)? What is the moving boundary work (kJ)? What is the temperature difference between the initial and final states expressed in degree R? What is the heat interaction (kJ)? Assume Cp(T) = 21 kJ/kmolK.Explanation / Answer
initital temperature is given by ideal gas =>T= PV/NR = (150*1000*0.5*40)/(1000*8.314)=360.83k =87.3C;
final temperature =>v1/v2 =T1/T2=>T2=360.83*1.3/0.5 =938.15k=665.15C;
work = Pdv= 150000*(0.8) = 120000J=120kJ;
tempearature difference = 938.15 -360.83 = 577.32K =577.32*9/5 =1039.17R
heat interaction = nCpdT = 577.32*21*25 =303kJ