Thermo dynamic processes

Sep 2012
1
0
In a cylinder with 1.2 mol of an ideal gas, initially at 3.60 x 10^5 pa
and 300k is compressed until the volume is halved.
there are 3 compressions. isothermal, adiabatic, and isobaric.

a) in which case is the absolute value of the change in interrnal energy of the gas the greatest? least?

Now, would it be different between compressed, and expand?
To answer part a would i apply the first law of thermodynamics to each process? would the adiabatic be the greatest in this case but the least expanding?

Thank you
 
Feb 2013
94
3
NM
In a cylinder with 1.2 mol of an ideal gas, initially at 3.60 x 10^5 pa
and 300k is compressed until the volume is halved.
there are 3 compressions. isothermal, adiabatic, and isobaric.

a) in which case is the absolute value of the change in interrnal energy of the gas the greatest? least?

Now, would it be different between compressed, and expand?
To answer part a would i apply the first law of thermodynamics to each process? would the adiabatic be the greatest in this case but the least expanding?

Thank you
Just looking at pV=nRT, and noting that the energy change is the integral of p dV, or it is the change of pV.

isothermal The temperature is the same, then heat was extracted from the system. V is half, p is double, pV is unchanged

adiabatic means no heat transfer to/from the system. Both p and T increase under compression.

isobaric The pressure is not allowed to change, so the compression has to be accomplished by decrease of T. pV after compression is half.