Complete the table below on the basis of the conservation of
Solution
FOR THE FIRST ROW OF THE TABLE----
Qin = 350 kJ, E1 = 1021 kJ, E2 = 860 kJ (E = E2 - E1 = 860 - 1021 = -161 kJ)
Wout = ? AND e2 - e1 = ?
MASS OF SYSTEM m (kg) IS NOT GIVEN, HENCE WE ASSUME IT TO BE UNIT MASS - THAT IS m = 1 kg
NOW AS PER THE ENERGY EQUATION OF THE CLOSED SYSTEM, WE USE BELOW FORMULAE--
Qin - Wout = E and e2 - e1 = E / m
So substituting values, we get Wout = Qin - E = 350 - (-161) = 350 + 161 = 511 kJ
& e2 - e1 = E / m = -161 / 1 = -161 kJ/kg
Therefore Wout = 511 kJ (Answer) and e2 - e1 = -161 kJ/kg (Answer)
FOR THE SECOND ROW OF THE TABLE---
Qin = 350 kJ, E1 = 550 kJ, Wout = 130 kJ, m = 5 kg (E = E2 - E1)
E2 = ? AND e2 - e1 = ?
NOW AS PER THE ENERGY EQUATION OF THE CLOSED SYSTEM, WE USE BELOW FORMULAE--
Qin - Wout = E and e2 - e1 = E / m
Substituting values in the above formula, we get E = Qin - Wout = 350 - 130 = 220 kJ
and since E = E2 - E1, we arrive at the substitution 220 = E2 - 550 which gives E2 = 220 + 550 = 770 kJ
Now as stated in formulae e2 - e1 = E / m, we get e2 - e1 = 220 / 5 = 44 kJ/kg
Therefore E2 = 770 kJ (Answer) and e2 - e1 = 44 kJ/kg (Answer)
