Question

Show that for a cyclic process involving isothermal reversible expansion and

reversible compression, the total entropy change is zero.

Answer 1

For reversible isothermal expansion
E1=q+w
=q+(-pdv)
=q-p(v2-v1)
And for compression
E2=q+p(v1-v2)
E2-E1=0
Delta E=0
(bcz for expansion V2 is greater than V1
And for compression V1 is greater than V2)
I hope it will help you

Answer 2

first enthalpy is simply the amount of heat in an object or the amount of heat released or absorbed during a reaction ,the total heat content within a system is what is refered to as the enthalpy .there are different types of reactions for instance redox reactions ,oxidation reaction and reduction reaction .in both the reactions there is either heat loss or heat gain

for a cyclic process involving isothermal reversion expansion and reversible compression ,the total enthalpy change is zero  ,this means that in reactions in reactions that can be reversed such that if you react two compounds then the end product can be reversed to form the initial reactants