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Introduction
Thermodynamics is the study of the energy, primarily heat energy, that is generated during chemical or physical reactions. Certain chemical reactions produce heat energy; these are referred to as exothermic reactions and have a negative enthalpy change. Others, referred to as endothermic reactions, absorb heat energy and produce a positive enthalpy change. However, thermodynamics is more than just about heat energy. The entropy change in a process describes the change in the level of organisation or disorganisation of reactants and products as changes occur. For example, converting one gramme of liquid water to gaseous water results in an increase in disorder, as the molecules are considerably more disorganised in a gas than in a liquid. The increase in disorder is quantified as an increase in entropy, with a positive change in entropy.
The occurrence of a chemical reaction or physical change is dependent on both the enthalpy and the entropy of the process, both of which may be estimated from tabulated information. In the free energy, which is the third and most essential thermodynamic term, these two terms are merged. If the change in free energy is negative, the reaction will proceed to the right; this reaction is referred to as a spontaneous reaction. If the change in free energy is positive, the reaction will go to the left. Assuming the sign is positive, the reaction will not occur in the manner specified by the formula; this reaction is nonspontaneous. It is possible to make an extremely accurate prediction about whether a reaction will occur or will not occur by using tabular data to compute the change in free energy.
Chemists can make extensive use of thermodynamics. After all, nature, left to its own devices, is always striving to conserve energy. Thermodynamics informs the scientist of the direction in which this minimum exists.
Internal Energy
It is the amount of energy that a system saves inside. This energy represents the system’s overall energy. It could be any type of energy: kinetic or potential energy, for example. We are aware of how energy is transformed. We are aware that energy can be transferred rather than created or destroyed.
The fundamental thermodynamic concepts provide insight into the energy shift associated with a chemical reaction system. When heat is introduced or removed from a system, the internal energy of the system may change. We could say that work is performed on or by the system. Additionally, we can express it as: matter enters or exits the system.
Thermodynamic System and the Surrounding
System
The system denotes the region of the universe being observed. A thermodynamic system is a subatomic particle with a definite boundary on which our attention is focused. The system boundary can be physical or fictitious, fixed or moveable.
When physical properties and chemical compositions are consistent throughout a system, they are considered to be homogenous. On the other hand, a system is termed heterogeneous if it is composed of components with disparate physical and chemical properties. A system can be classified into three groups based on the manner in which matter and energy enter and exit. Three distinct sorts of systems exist.
Open System
The open system is one that is capable of exchanging both matter and energy with its environment. As a result, in an open system, mass and energy can be communicated between the system and its surroundings. Due to the fact that hot coffee in an open flask gains and loses matter as well as energy, it is an example of an open system. Steam turbine is an example of an open system.
Closed System
The closed system exchanges the energy with its environment but not with the matter. Energy is transmitted across the closed system’s boundary, but mass is not. Refrigerators and gas compression in piston-cylinder assembly are examples of closed systems. Coffee in a stainless flask is also an example of a closed system, as energy can pass through the cell walls but not matter.
Isolated System
A system that is isolated from its environment is one that is unable to exchange matter or energy with it. There is no such thing as a perfectly isolated system. On the other hand, an isolated system is completely sealed to prevent matter entry or exit and is thermally insulated to prevent heat movement. It is claimed that the cosmos is self-contained. A hot cup of coffee in a corked thermos flask is an example of an isolated system since it cannot gain or lose energy or matter.
Boundary
A barrier separates the system from its surroundings. It may be stationary, moveable, or fictitious. It will take up no space in terms of volume or mass.
Surrounding
The remainder of the universe that is not included in the system is referred to as the surrounding. The term “surrounding” refers to everything external to the system that has an effect on its behaviour directly. In other words, anything outside the system is considered to be part of the environment. The universe is composed of the system and its surroundings.
On the other hand, changes to the system have no influence on the entire universe. As a result, the surroundings are that portion of the remaining universe that is capable of interacting with the system. In general, the surrounds are described as an area of space that is immediately adjacent to another area of space.
Thermodynamic Properties
Thermodynamics is concerned with the behaviour of large chemical entities such as atoms and molecules. A system’s macroscopic quantities are determined by the bulk behaviour of matter. Thermodynamic properties are defined as characteristics of a system that can be utilised to specify its state. Thermodynamic qualities fall into two types, as seen below.
- Extensive Property- Extensive properties are those of a system whose value is proportional to the amount or size of material present. The value of extensive features is proportional to the mass of the system. Among the several attributes are internal energy, entropy, free energy, and enthalpy.
- Intensive Property- Intensive properties are those of a system whose value is independent of the quantity or size of the material present. An intensive substance’s qualities are those that are unrelated to the amount of substance present. Among the several intense attributes are vapour pressure, pressure, viscosity, surface tension, and temperature.
Conclusion
Thermodynamics deals with concepts such as heat and temperature, as well as the exchange of heat and other forms of energy. The thermodynamics branch of physics is concerned with the study of various forms of energy and its conversion. Three fundamental thermodynamic principles govern the behaviour of these quantities and provide a quantitative description. William Thomson originated the term thermodynamics in 1749.
