Question

90 kJ of heat is supplied to a system at a constant volume. The system rejects 95 kJ of heat

at constant pressure and 18 kJ of work is done on it. The system is brought to original state

by adiabatic process. Determine i) Adiabatic Work ii) Internal Energy at all end states.

Take initial state value of Internal Energy is 105 Kj​

Answer 1

Step-by-step explanation:

Given  

90 k J of heat is supplied to a system at a constant volume. The system rejects 95 k J of heat at constant pressure and 18 k J of work   is done on it. The system is brought to original state  by adiabatic process. Determine i) Adiabatic Work ii) Internal Energy at all end states.

Take initial state value of Internal Energy is 105 Kj​

Given heat supplied at constant volume = 90 kJ

Heat rejected at constant pressure = - 95 kJ

Work done will be – 18J

So initial value of internal Ui = 105kJ

Process constant volume l – m

So W = 0

Q = 90

90 = Um – Ul

Um = Ui + 90

      = 105 + 90

      = 195 kJ

Process constant pressure m – n:

             Q = (Un – Um) + Wm – n

    So – 95 = (Un – Um) – 18

Therefore Un – Um = -77 kJ

Now Un = 195 – 77 – 118kJ

Since adiabatic process, Qn-l = 0

Therefore ʃΔQ =90-95 = - 5 kJ

        So ʃΔW = - 18 + Wn-l = - 5

Wn – l = - 5 + 18 = 13 kJ

Therefore Wn – l = 13kJ Ul = 105kJ, Um = 195kJ and Un = 118kJ