How Many Laws are There in Thermodynamics

Introduction

There are 4 laws of thermodynamics. The study of how heat, work, temperature, and energy interact is known as thermodynamics. The science of thermodynamics, in its broadest sense, is concerned with the movement of energy from one location or form to another. The fundamental idea is that heat is an energy type that may be equated to a specific quantity of mechanical work. Earlier in 1798, when British military engineer Count Rumford (Sir Benjamin Thompson) learned that indefinite amounts of heat could be produced while drilling cannon barrels and that the amount of heat produced is proportional to the work done while turning a blunt boring tool, the heat was not formally recognised as a form of energy. The foundation of thermodynamics' theoretical framework was laid by Rumford's discovery of the connection between heat produced and work performed.

Thermodynamic Principle

To apply thermodynamic principles, one must first identify a system that is different from its surroundings in some way. A system's current state is referred to as its thermodynamic state. The temperature, pressure, and volume of the gas in a cylinder with a moving piston serve to determine the state of the system. These characteristics are parameters that are fixed at each state and regardless of how the system got there. They have specific values. In other words, any change in the value of a property depends simply on the system's starting and final states, not on the route it takes to get there. These qualities are known as state functions. However, depending on the specifics of the expansion process, the labour required as the piston advances, the gas expands, and the heat that the gas receives from its surroundings rely on the specifics of how the expansion takes place.

Thermodynamic Equilibrium

Thermodynamic equilibrium, which prevents a system's state from changing spontaneously, is a key idea. For instance, if the temperature and pressure inside a cylinder with a moving piston are uniform and if the force acting to restrain the piston is just strong enough to prevent it from moving, the gas will be in equilibrium. The system may then only be forced to transition to a new state by an externally imposed change in one of the state functions, such as the temperature. By adjusting the piston, we can add heat or increase volume.

The Laws of Thermodynamics

1. The Zeroth Law of Thermodynamics.

The first two systems are in thermal equilibrium with each other when they are both in thermal equilibrium with a third system. In other words, if two items are in thermal equilibrium with one another and are both at the same temperature, then the third object is also at the same temperature as the other two.

2. First Law of Thermodynamics (Law of Conservation of Energy)

The difference between heat added to the system from its surroundings and work done by the system on its surroundings represents the change in a system's internal energy.

The difference between the heat Q delivered to the system from its surroundings and the work W done by the system on its surroundings, if the system is not isolated, determines the change in a system's internal energy U.

3. The Second Law of Thermodynamics

Heat cannot naturally move from a colder to a hotter area, or, put differently, heat at a particular temperature cannot completely transform into work.

As a result, the entropy of a closed system, or the amount of heat energy per unit of temperature, rises over time and eventually reaches a maximum value. As a result, all closed systems tend to a state of equilibrium when entropy is at its peak and no energy is available for productive labour.

4. The Third Law of Thermodynamics

The entropy of an isolated system approaches a constant value as the temperature of the system approaches absolute zero. Since it becomes increasingly harder to remove energy from a system as it gets closer to absolute zero, this theorem practically means that reaching absolute zero is impossible.

Conclusion

The rules of thermodynamics, in particular, provide a thorough explanation of all changes in a system's energy state and its capacity to do beneficial work on its surroundings. Any physical system will naturally work toward a state of equilibrium that may be characterised by mentioning certain aspects of it, like pressure, temperature, or chemical makeup. These characteristics typically alter if external limitations are allowed to shift. The system's equilibrium state is predicted by the three laws of thermodynamics, which also describe these changes. According to the first law, no matter how energy is changed from one form to another, its overall amount never changes. According to the second law, entropy does not diminish in a closed system. The third law indicates that when a system gets closer to zero degrees Fahrenheit, further energy extraction gets harder and harder until it's potentially impossible.