What’s the Difference Between Entropy and Enthalpy?

Entropy is an attribute demonstrating the randomness of molecules. It is represented as the total heat content of a system. In other words, it is the property of the system, deciding the percentage of the heat that can be converted into work.

If the randomness of molecules is considerable, the more swiftly entropy of the process increases. Subsequently, the percentage of heat converted into work will be less. Hence, it can be concluded that entropy is the function of the quantity of heat.

Enthalpy represents the heat content of the system. As we all know that heat can possibly go in or out of the system. So, the change of heat, in case of a chemical reaction, is defined as enthalpy change. In other words, it is energy procured by the sum of internal energy and flow energy.

It is the measure of the total heat present in the thermodynamic system where the pressure is constant.

With the help of the above information and the table, it can be perceived that Enthalpy is the total of energies. In contrast, entropy is the measure of the change in enthalpy/temperature. Let's understand this with the help of an example-

1) Suppose you have Rs. 1000 in total and someone gave you Rs. 500. It will make a considerable difference. Doesn’t it?

2) Now, let's say you already have Rs. 1,00,000,00, and you have got an additional Rs. 500 from someone. Although the change is the same, it won't make a bigger difference and won't have any considerable impact on your wealth.

In order to calculate the ratio, we need to divide the change with the amount you initially had-  

So, as per the first case, it is 500/1000= 0.5
As per the second case, it is 500/10000000= 0.00005

This ratio is called entropy, which is the heat supplied, divided by the temperature directly related to Enthalpy.