Definitions for enthalpy
ˈɛn θæl pi, ɛnˈθæl-en·thalpy

Princeton's WordNetRate this definition:5.0 / 2 votes

1. heat content, total heat, enthalpy, Hnoun

   (thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure

   "enthalpy is the amount of energy in a system capable of doing mechanical work"

WiktionaryRate this definition:0.0 / 0 votes

1. enthalpynoun

   In thermodynamics, a measure of the heat content of a chemical or physical system.

   uE000147219uE001, where H is enthalpy, U is internal energy, p is pressure, and V is volume.

2. Etymology: From ἐνθάλπω.

WikipediaRate this definition:0.0 / 0 votes

1. Enthalpy

   Enthalpy (listen), a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant pressure, which is conveniently provided by the large ambient atmosphere. The pressure–volume term expresses the work required to establish the system's physical dimensions, i.e. to make room for it by displacing its surroundings. The pressure-volume term is very small for solids and liquids at common conditions, and fairly small for gases. Therefore, enthalpy is a stand-in for energy in chemical systems; bond, lattice, solvation and other "energies" in chemistry are actually enthalpy differences. As a state function, enthalpy depends only on the final configuration of internal energy, pressure, and volume, not on the path taken to achieve it. In the International System of Units (SI), the unit of measurement for enthalpy is the joule. Other historical conventional units still in use include the calorie and the British thermal unit (BTU). The total enthalpy of a system cannot be measured directly because the internal energy contains components that are unknown, not easily accessible, or are not of interest in thermodynamics. In practice, a change in enthalpy is the preferred expression for measurements at constant pressure because it simplifies the description of energy transfer. When transfer of matter into or out of the system is also prevented and no electrical or shaft work is done, at constant pressure the enthalpy change equals the energy exchanged with the environment by heat. In chemistry, the standard enthalpy of reaction is the enthalpy change when reactants in their standard states (p = 1 bar; usually T = 298 K) change to products in their standard states. This quantity is the standard heat of reaction at constant pressure and temperature, but it can be measured by calorimetric methods even if the temperature does vary during the measurement, provided that the initial and final pressure and temperature correspond to the standard state. The value does not depend on the path from initial to final state because enthalpy is a state function. Enthalpies of chemical substances are usually listed for 1 bar (100 kPa) pressure as a standard state. Enthalpies and enthalpy changes for reactions vary as a function of temperature, but tables generally list the standard heats of formation of substances at 25 °C (298 K). For endothermic (heat-absorbing) processes, the change ΔH is a positive value; for exothermic (heat-releasing) processes it is negative. The enthalpy of an ideal gas is independent of its pressure or volume, and depends only on its temperature, which correlates to its thermal energy. Real gases at common temperatures and pressures often closely approximate this behavior, which simplifies practical thermodynamic design and analysis.

ChatGPTRate this definition:0.0 / 0 votes

1. enthalpy

   Enthalpy is a concept in physical chemistry which describes the total heat content of a system. It is a thermodynamic potential, often denoted by the symbol H, and is equivalent to the internal energy of the system plus the product of pressure and volume. It is often used in measurements of energy change during chemical reactions, particularly in constant pressure conditions. Changes in enthalpy can be used to calculate the quantity of heat transferred in a chemical or physical process under constant pressure conditions.

WikidataRate this definition:3.0 / 1 vote

1. Enthalpy

   Enthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure. Enthalpy is a thermodynamic potential. It is a state function and an extensive quantity. The unit of measurement for enthalpy in the International System of Units is the joule, but other historical, conventional units are still in use, such as the British thermal unit and the calorie. The enthalpy is the preferred expression of system energy changes in many chemical, biological, and physical measurements, because it simplifies certain descriptions of energy transfer. Enthalpy change accounts for energy transferred to the environment at constant pressure through expansion or heating. The total enthalpy, H, of a system cannot be measured directly. Thus, change in enthalpy, ΔH, is a more useful quantity than its absolute value. The change ΔH is positive in endothermic reactions, and negative in heat-releasing exothermic processes. ΔH of a system is equal to the sum of non-mechanical work done on it and the heat supplied to it.

Matched Categories

1. • Physical Property
   • Thermodynamics

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How to say enthalpy in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of enthalpy in Chaldean Numerology is: 5

2. Pythagorean Numerology

   The numerical value of enthalpy in Pythagorean Numerology is: 2

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References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=enthalpy
2. ^ Wiktionary
   https://en.wiktionary.org/wiki/Enthalpy
3. ^ Wikipedia
   https://en.wikipedia.org/wiki/Enthalpy
4. ^ ChatGPT
   https://chat.openai.com
5. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=enthalpy