What is the Difference Between First Law and Second Law of Thermodynamics?
🆚 Go to Comparative Table 🆚The First Law and Second Law of Thermodynamics are fundamental laws that describe the behavior of energy and entropy in natural processes. The main differences between them are:
- First Law of Thermodynamics: This law focuses on the conservation of energy in processes. It states that energy cannot be created or destroyed; it can only change form or be transferred from one object to another. The internal energy of a system is the difference between the energy it absorbs and the energy it releases. In summary, the First Law deals with the quantity of energy.
- Second Law of Thermodynamics: This law concerns the directionality of processes and the concept of entropy. Entropy is a measure of the disorder or randomness of a system. The Second Law states that for a spontaneous process, the entropy of the universe increases. In other words, it deals with the quality and direction of energy.
Another key difference between the two laws is that the First Law of Thermodynamics describes the internal energy of a system and how it changes due to heat and work interactions, whereas the Second Law of Thermodynamics describes the nature of energy and its transfer in the universe. In essence, the First Law focuses on the total amount of energy in the universe and its conservation, while the Second Law focuses on the way energy is used or transferred in natural processes, and it relates to the increase in entropy or disorder.
Comparative Table: First Law vs Second Law of Thermodynamics
The main differences between the First Law and Second Law of Thermodynamics are related to the conservation of energy and the direction of energy transfer. Here is a table summarizing the differences:
| Feature | First Law of Thermodynamics | Second Law of Thermodynamics |
|---|---|---|
| Statement | Energy can neither be created nor destroyed, but it can be transferred between the system and its surroundings. | The entropy (degree of disorder) of an isolated system never decreases; it always increases. |
| Expression | ΔE = Q + W, where ΔE is the change in internal energy, Q is the heat transferred, and W is the work done. | ΔS = ΔS(system) + ΔS(surrounding) > 0, where ΔS is the change in entropy. |
| Focus | Conservation of energy. | Direction of energy transfer and the concept of entropy. |
In summary, the First Law of Thermodynamics deals with the conservation of energy and how energy can be transferred between a system and its surroundings. On the other hand, the Second Law of Thermodynamics focuses on the direction of energy transfer and the concept of entropy, which is a measure of the degree of disorder in a system.
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