What is the difference between entropy and enthalpy?
The thermodynamic system comprises of entropy and enthalpy. Entropy change and enthalpy change tend to confuse many students studying chemistry.
The core difference between entropy and enthalpy in points form is that entropy is the measure of the degree of disorder while enthalpy represents the total heat content.
What Is Entropy?
Entropy is the degree of randomness or extent of a disorder in a chemical reaction. The second law of thermodynamics state that entropy of an isolated system will always increase.
Therefore, the randomness of a chemical reaction will increase when the number of molecules involved increases.
You should note that the reaction move towards a higher level of disorder when products used are greater than reactants.
What Is Enthalpy?
Enthalpy refers to the heat change when the reactions occur at constant pressure. Enthalpy is a state function which implies that the value will not change regardless of the chemical route taken to obtain the products
The reaction of enthalpy exists in form of enthalpy of reaction, enthalpy of formation, enthalpy of combustion, enthalpy of neutralization and enthalpy of solution.
Comparison Chart: Entropy Vs Enthalpy
| Basic Terms | Entropy | Enthalpy |
| Meaning | It is the measure of randomness of a disorder of a chemical reaction | It is the measure of heat change under constant pressure and temperature |
| Units of Measurement | JK-1 | Jmol-1 |
| Requirements | No limits | Constant pressure and temperature |
| Formula | S=q/T | H=U+PV |
| Nature | It is a property | It is a kind of energy |
| Abbreviation | S | H |
| Discovered by | Rudolf Clausius | Heike Kamerlingh Onnes |
| System Favors | Minimum entropy | Maximum enthalpy |
Core Difference Between Entropy and Enthalpy
- Entropy is the measure of randomness or extent of disorder in a chemical process whereas enthalpy is the measure of heat change at constant pressure
- The S.I unit of entropy is JK-1 while that of enthalpy is Jmol-1
- Entropy is measured by the difference between the heat change of the chemical process and the temperature while enthalpy represents heat change at standard conditions.
- Entropy is a property while enthalpy is a type of energy
- Entropy is denoted as s while enthalpy as H.
- The formula of calculating entropy is s=q/t whereas that of enthalpy is H=U+PV
- The thermodynamic systems tend to favor minimum entropy while in enthalpy it favors maximum enthalpy
- The scientist behind the discovery of enthalpy is Heike Kamerlingh Onnes while entropy is Rudolf Clausius.
Read More: Difference between Compounds and Mixture
Comparison Video
Summary
The above-mentioned difference between entropy and enthalpy in points is enough to combat the confusion around these thermodynamic systems. Take time to read through then learn more about the difference between enthalpy and internal energy change.