Question

Does isentropic means adiabatic?

Answer 1

Hint: In order to describe two particular chemical processes that take place in thermodynamic systems, isentropic and adiabatic terms are used. The term isentropic refers to the thermodynamic process having constant entropy. This process is an idealized thermodynamic process. The other term adiabatic refers to the thermodynamic process in which heat is constant that there is no loss or gain in the heat energy by the system. Let us see if isentropic means adiabatic in the following paragraphs.

Complete answer:
A thermodynamic process in which no heat transfer takes place is known as the adiabatic process. There are two types of adiabatic processes that are reversible and irreversible. The reversible adiabatic process is what is called an isentropic process. An isentropic process is defined as the process in which there is no entropy change. An isentropic process is a special case of an adiabatic process in which there is no transfer of heat. Therefore we can say that isentropic means adiabatic but the reverse is not always true. That is the adiabatic process need not be an isentropic process.

Note:
The main difference between the adiabatic and isentropic processes is that in the adiabatic process there is constant heat energy and in the isentropic process there is constant entropy. We know that differentiating a constant term would give us zero.
\[dE = \dfrac{{dQ}}{{dt}}\]
Here \[dE\]is the change in entropy.
          \[dQ\] is the change in heat
Therefore in the reversible adiabatic since there is no transfer of heat that is \[dQ = 0\]. Therefore the above equation becomes \[dE = 0\] which represents an isentropic process. Some real-life examples of the isentropic process are an expansion of steam in steam turbines, gas in gas turbines, and compression of air in compressors.