Laws of Thermodynamics

Thermodynamics states the relationship between heat, work, temperature, and energy. The change of energy in a system or matter is defined by the help of the laws of thermodynamics. These laws state on the assumption that energy can be disseminated either in the form of heat or work. One example of this is that we start to sweat when we’re in a big crowd. There is a transfer of energy that makes you feel hot and, as a result, causes you to sweat. This occurs as a result of a transfer of heat between 2 systems. The energy is not lost or gained, but instead, it is circulated in the same environment between 2 or more systems.  

Define the Zeroth Law of Thermodynamics 

Ralph H. Fowler founded the Zeroth Law of Thermodynamics. It is considered one of the four laws of thermodynamics, but this was developed much later than the other laws of thermodynamics. This law defines the relationship between 2 thermodynamic systems stating that if two systems (Thermodynamic) are in a state of equilibrium with the third thermodynamic system, then those two systems are in thermal equilibrium with each other. Thermal equilibrium between two or more systems is transitive. This law is stated based on the measurement of temperature. The systems that are in equilibrium with each other would thus, have the same temperature. The zeroth law of thermodynamics did not consider the transfer of heat or energy when the objects are not in physical contact with each other and stated that no heat flow would occur when the systems are in equilibrium. 

Define the First Law of Thermodynamics 

Of the three laws of thermodynamics, the first law states that energy is constant and cannot be created or destroyed. It can also be called conservation of energy, and this law explains how energy can only be exchanged between a system in the form of heat emission or work but is never destroyed or created. This can be explained mathematically using the formula.  

ΔE = q + w

In this formula, q represents heat, and w represents physical or mechanical work performance. Energy does not disseminate or disappear. If there is a gain of energy by the system, there has been a corresponding loss in the energy levels in the surroundings and vice versa. This law also defines the existence of internal energy of a system and states that work and heat are modes of transferring energy. This law is very similar to the conservation of energy. 

Define Second Law of Thermodynamics 

The second law, out of the three laws of thermodynamics, explains how spontaneity, which is scientifically called entropy, increases over time. This law deals with the clear distinction between spontaneous and non-spontaneous processes. Spontaneous processes are natural and occur independently without needing to be driven or initiated. Physicist William Thomson gave this law. Under this law, there were 2 distinctions of the universe introduced, one was the system, and the other was the surroundings. The system is being investigated or researched, and the surroundings are the rest of the universe except the surroundings. This law states that the entropy or spontaneity of an isolated system increases gradually over time. 

What is the Third Law of Thermodynamics? 

The third of the laws of thermodynamics states that the spontaneity or entropy of a perfect crystal at absolute Kelvin, i.e. absolute 0, is 0, and it has no entropy or spontaneity. Absolute 0 is the point where the motion of the particles becomes 0 or constant, and a perfect crystal refers to the crystalline state when the ions or atoms are in well-defined positions in a highly-ordered crystalline lattice and have achieved thermodynamic equilibrium. The third law of thermodynamics is represented mathematically in the form of –

S – S0 = kB lnΩ

Where,

S = The entropy of the system.

S0 = The initial entropy.

kB = Boltzmann’s constant = 1.38×10−23 J K−1

Ω = The total number of microstates that are consistent with the system’s macroscopic configuration.

This law helps define the sign of spontaneity/ entropy and also calculates the absolute entropy of a substance at any given temperature. An example of this law can be how random the atoms of steam and water vapour move in their gaseous forms at a high temperature. In this case, spontaneity is said to be low or 0. When the movements of the elements get restricted, then, the vapours cool down and gradually turn into ice. 

Conclusion 

Thermodynamics plays an important role in understanding the functioning of work and heat energy transfer. The application of thermodynamics extends right from the bathroom to the desert and causes problems. The laws of thermodynamics are essential as they define the laws of thermodynamics and the relationship between energy and thermodynamics study. One of the examples of thermodynamics is the study of different types of power plants which includes study plants and thermal power plants. So it becomes necessary for the study of thermodynamics.