Fundamental Thermodynamic Relation

(noun)

In thermodynamics, the fundamental thermodynamic relation expresses an infinitesimal change in internal energy in terms of infinitesimal changes in entropy, and volume for a closed system in thermal equilibrium in the following way: dU=TdS-PdV. Here, U is internal energy, T is absolute temperature, S is entropy, P is pressure and V is volume.

Related Terms

Examples of Fundamental Thermodynamic Relation in the following topics:

  • Specific Heat for an Ideal Gas at Constant Pressure and Volume

    • It is easier to measure the heat capacity at constant pressure (allowing the material to expand or contract freely) and solve for the heat capacity at constant volume using mathematical relationships derived from the basic thermodynamic laws.
    • This equation reduces simply to what is known as Mayer's relation :
    • It is a simple equation relating the heat capacities under constant temperature and under constant pressure.
    • Julius Robert von Mayer (November 25, 1814 – March 20, 1878), a German physician and physicist, was one of the founders of thermodynamics.
    • He is best known for his 1841 enunciation of one of the original statements of the conservation of energy (or what is now known as one of the first versions of the first law of thermodynamics): "Energy can be neither created nor destroyed. " In 1842, Mayer described the vital chemical process now referred to as oxidation as the primary source of energy for any living creature.

  • The First Law of Thermodynamics

    • The first law of thermodynamics states that energy can be transferred or transformed, but cannot be created or destroyed.
    • The first law of thermodynamics deals with the total amount of energy in the universe.
    • Thermodynamics often divides the universe into two categories: the system and its surroundings.
    • Another useful form of the first law of thermodynamics relates heat and work for the change in energy of the internal system:
    • A basic diagram showing the fundamental distinction between the system and its surroundings in thermodynamics.

  • The Second Law

    • The second law of thermodynamics deals with the direction taken by spontaneous processes.
    • If the process can go in only one direction, then the reverse path differs fundamentally and the process cannot be reversible.
    • The law that forbids these processes is called the second law of thermodynamics .
    • Like all natural laws, the second law of thermodynamics gives insights into nature, and its several statements imply that it is broadly applicable, fundamentally affecting many apparently disparate processes.
    • Contrast the concept of irreversibility between the First and Second Laws of Thermodynamics

  • The Three Laws of Thermodynamics

    • The laws of thermodynamics define fundamental physical quantities (temperature, energy, and entropy) that characterize thermodynamic systems.
    • In order to avoid confusion, scientists discuss thermodynamic values in reference to a system and its surroundings.
    • The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another.
    • The second law of thermodynamics says that the entropy of any isolated system always increases.
    • The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero.

  • The First Law

    • The first law of thermodynamics is a version of the law of conservation of energy specialized for thermodynamic systems.
    • In equation form, the first law of thermodynamics is
    • In this video I continue with my series of tutorial videos on Thermal Physics and Thermodynamics.
    • The change in the internal energy of the system, ΔU, is related to heat and work by the first law of thermodynamics, ΔU=Q−W.
    • Explain how the net heat transferred and net work done in a system relate to the first law of thermodynamics

  • Matter Exists in Space and Time

    • The principle topics covered in elementary mechanics are: fundamental abstracts, the Newtonian system, position and velocity, and Newton's second law.
    • This section re-introduces some fundamental terms and methods of science that form the basis of Engineering Thermodynamics.
    • To assist students in learning beginning-level thermodynamics; some review to set things straight is required.
    • Fundamental Abstracts: The accumulated observations of ourselves are categorized into our "knowledge. " From time to time, the essence of "all we know" is formulated as an abstract, being something we all agree that we know.
    • Examples of this section relate to representation of space as an origin, coordinates and a unit vector basis.

  • Temperature

    • Although there is an entire field of study devoted to measuring temperature (thermometry), the focus of this section is on the fundamental measurements of temperature.
    • Temperature-related phenomena were always being observed.
    • Today that is referred to as 0 K on the Kelvin thermodynamic temperature scale.
    • The fundamental requirements of the practice involve accuracy, a standard, linearity, and reproducibility.
    • The SI unit, chosen for its simplicity and relationship to thermodynamics, is the kelvin, named in honor of Lord Kelvin.

  • LTE

    • To derive these relations we have not made any assumptions about whether the photons or the matter are in thermal equilibrium with themselves or each other.
    • An extremely useful assumption is that the matter is in thermal equilibrium at least locally (Local Thermodynamic Equilibrium).
    • In this case the ratio of the number of atoms in the various states is determined by the condition of thermodynamic equilibrium
    • Because the source function equals the blackbody function, does this mean that sources in local thermodynamic equilibrium emit blackbody radiation?

  • Absolute Temperature

    • Thermodynamic temperature is the absolute measure of temperature.
    • It is one of the principal parameters of thermodynamics and kinetic theory of gases.
    • Thermodynamic temperature is an "absolute" scale because it is the measure of the fundamental property underlying temperature: its null or zero point ("absolute zero") is the temperature at which the particle constituents of matter have minimal motion and cannot become any colder.
    • By using the absolute temperature scale (Kelvin system), which is the most commonly used thermodynamic temperature, we have shown that the average translational kinetic energy (KE) of a particle in a gas has a simple relationship to the temperature:

  • Thermodynamics of Redox Reactions

    • The thermodynamics of redox reactions can be determined using their standard reduction potentials and the Nernst equation.
    • In order to calculate thermodynamic quantities like change in Gibbs free energy $\Delta G$ for a general redox reaction, an equation called the Nernst equation must be used.
    • Walther Nernst was a German chemist and physicist who developed an equation in the early 20th century to relate reduction potential, temperature, concentration, and moles of electrons transferred.