A gas is to be expanded from initial state i to final state

A gas is to be expanded from initial state i to final state f along either path 1 or path 2 on a p-V diagram. Path 1 consists of three steps: an isothermal expansion (work is 40 J in magnitude), an adiabatieexpansion (work is 19 J in magnitude), and another isothermal expansion (work is 26 J in magnitude). Path 2 consists of two steps: a pressure reduction at constant volume and an expansion at constant pressure. What is the change in the internal energy of the gas along path 2?

Solution

Solution:

Work done in isothermal expansion = W1 = 40 j

Work done in adiabatic expansion = W2 = 19 j

Work done in another isothermal expansion = 26 j

An Isothermal process is one in which there will be no change in temperature .

Since internal energy change = Eint = n Cv delta T , for n isothermal process , delta T = 0

so No change in internal energy .

An adiabatic process is one in which there will be No heat entering or leaving the system. So Q=0.

All the work done is in the form of change ininternal energy.

Eint = Q-W= -19 J along the pah 2.