Please do all parts and show work and explain, thank you. 7. a. I have two conta
ID: 885637 • Letter: P
Question
Please do all parts and show work and explain, thank you.
7. a. I have two containers connected to each other by a valve. One has a gas at some pressure, the other is under vacuum. If I open the valve, what is the amount of work done by the gas expanding into the vacuum? b. IfI enclose the whole thing in glass wool (i.e. I totally insulate it), how much heat is exchanged (Aq)? c. What is the change in internal energy in this example (expansion into a vacuum while the whole object is thermally insulated)? (6 pts) 8. I have a metal piston filled with a room temperature perfect gas at 1 atm ofpressure. I compress the gas significantly by pushing on the plunger. The gas gets very hot due to the compression, but then cools back to room temperature since it is in a non-insulating metal cylinder. a. What is the net AU and AH (and why)? b. While still applying pressure on the plunger after it cools to room temperature, I wrap it in insulating glass wool to make the system adiabatic. I then suddenly stop pushing it. As no heat can be exchanged with the outside, tell me if the piston will expand, compress, or stay the same and (3 pts) (3 pts)Explanation / Answer
The work done by the gas is zero since it is expanding into vacuum
Since from first law of thermodynamics chane in internal energy =Q+W
work done is zero and Q is zero ( since there is insulation ), change in internal energy=0
8. Since the gas is perfect and it has been brought to the room temperature, it becomes constant temperature process and del U and delH are both zeros since they depend only on temperature,
b. Even though the system is adiabatic from first law of thermodynamics
del U= Q+W , Q =0
del U= W , the gas expands because there is change in internal energy when pressure is applied.