Question

Isothermal and irreversible reactions, what is the difference between 1-step and 2-step process? How are they calculated differently?

Answer 1

Isothermal process are those in which the temperature of the system remains constant throughout the process.

Irreversible process are those in which the cannot be brought back to the initial stage at which it was started by any means. These are those which are not reversible in nature.

Process involving isothermal change have change in internal energy zero. So from the 1st law of thermodynamics , work done will be equal heat exchange .

I.e ∆Q= ∆U + ∆W , here ∆U= 0 so ∆Q= ∆W.

Now the process can be either reversible or irreversible. Work done can be calculated differently for both of these

For reversible process, work done is- W = -n*R*T ln V2/V1 where V2 is the final volume and V1 is the initial volume, R is universal gas constant, T is temperature and n is the number of moles.

For irreversible isothermal process ,

Work done= P* ∆V, where ∆V = V2-V1,

V2= final volume

V1= initial volume