Answer:
Q= - 7 KJ
Heat is rejected
Explanation:
In first process:
Process is adiabatic so heat transfer will be zero.
Q= 0 For adiabatic process
Now from first law of thermodynamics
Q = ΔU + W
ΔU is the change in internal energy
Q is the heat transfer
W is the work.
So here Q= 0
And work is transfer to the system .It means that work done on the system so it will be taken as negative.
W= - 12 KJ
Q = ΔU + W
0 = ΔU -12
ΔU = 12 KJ
It means that in first process internal energy of system increase.
In second process:
non-adiabatic process and work done by system is 5 KJ.
Q = ΔU + W
U is the point function and it does not depends on the path follows it depends only on final and initial states.
So fro second process
ΔU = - 12 KJ
Q= -12 + 5
Q= - 7 KJ
In magnitude Q= 7 KJ
It mean that heat is rejected from the system because it give negative sign.
