Take an example that you have a bag of balls and if you draw one ball from the bag then how many possible ways to arrange the balls together on the table. Now draw one more ball from the bag and try to find out the answer of same question. Repeat the process until the balls are not ended in the bag. Obviously, there are multiple ways to arrange the bag of ball and entropy concept is somewhat similar in Chemistry. Let us see how it works actually.
Entropy is defined as the total number of ways how a system can be arranged. The higher the entropy, the more ways the system is disordered. Another good example to state the definition of Entropy is Spraying perfume at one corner of the room, so what will happen next? The perfume will not stay in one corner only but its fragrance can be felt everywhere. So, from an ordered stage, perfume reached to disordered stage by spreading throughout the room. I hope you must have a better idea of Entropy here with this example.
This was second lay of thermodynamics where the concept of Entropy came into existence. Entropy is basically a thermodynamics function that is needed to calculate the randomness of a produce or system. For example, in case of solid where particles are not free to move frequently, the Entropy is less as compared to gas particles that can be disarranged in a matter of minutes. In the case of gas particles, Entropy is generally higher when compared to solid ones.
Here is given the Entropy formula how it can be used to calculated the value of surroundings with different equations.