Alright so my friends and I have been trying really hard on our new assignment, and there are some problems that we still can't do. It's like no matter how hard we try the book doesn't explain it well enough for us to be confident in our answers. So Pleeease help!
1. A mixture of hydrogen and oxygen is enclosed in a rigid insulating container and exploded by a spark. The temperature and pressure both increase. Neglect the small amount of energy provided by the spark itself.
A) Has there been a flow of heat into the system.
B)Has any work been done by the system.
C)Has there been any change in internal energy U of the system?
2.The water in a rigid. insulated cylindrical tank is set in rotation and left to itself. It is eventually brought to rest by viscous forces. The tank and the water constitute the system.
A)Is any work done during the process in which the water is brought to rest?
B)Is there a flow of heat?
C)Is there any change in the internal energy U?
3.Compressing the system represented in the figure along the adiabatic path a-c requires 1000J. Compressing the system along b-c requires 1500J but 600J of heat flow out of the system.
A)Calculate the work done, the heat absorbed, and the internal energy change of the system in each process and in the total cycle a-b-c-a.
B)Sketch this cycle on a P-V diagram.
C)What are the limitations on the values that could be specified for process b-c given that 1000J are required to compress the system along a-c
1.A)There is no heat flow because the system is insulated.
B)Yes adiabatic work is done. (I'm not sure why though)
C)Yes the change in internal energy is equal to the adiabatic work done (I think it's an increase in energy.
2.A)Yes there is dissipative work caused by the viscous forces.
B)There is no flow of heat because the system is insulated.
C)Yes the change in internal energy equals the dissipative work (decrease in energy?)
3.A)For a-c I wrote there is 1000J work done, no heat flow, and 1000J change in energy.
For b-c there is 1500J work done, 600J heat flow, 2100J change in energy.
For a-b-c-a there is no heat absorbed, 600J work done, no change in internal energy.
I haven't yet sketched the diagram but I am not sure what to do for the limitations on the values that could be specified for b-c given that 1000J are required to compress the system along a-c.
Diagram for 3:
Thanks for the help