In thermodynamics, the word endothermic "within heating" describes a process or reaction that absorbs energy in the form of heat. Its etymology stems from the Greek prefix endo-, meaning “inside” and the Greek suffix –thermic, meaning “to heat”. The opposite of an endothermic process is an exothermic process, one that releases energy in the form of heat. The term “endothermic” was coined by Marcellin Berthelot. A warm-blooded (homeothermic) animal is one that can keep its core body temperature at a nearly constant level regardless of the temperature of the surrounding environment (that is, to maintain thermal homeostasis) . This can involve not only the ability to generate heat, but also the ability to cool down... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... In thermodynamics, the word exothermic outside heating describes a process or reaction that releases energy usually in the form of heat, but it can also release energy in form of light (e. ... Marcellin Berthelot Marcellin (or Marcelin) Pierre Eugène Berthelot (October 25, 1827 - March 18, 1907) was a French chemist and politician noted in thermochemistry for the Thomsen-Berthelot principle. ...

The concept is frequently applied in physical sciences to e.g. chemical reactions, where thermal energy (heat) is converted to chemical bond energy. Physical science is the branch of science including chemistry and physics, usually contrasted with the social sciences and sometimes including and sometimes contrasted with natural or biological science. ... Chemical reactions are also known as chemical changes. ... In thermal physics, thermal energy is the energy portion of a system that increases with its temperature. ... In chemistry, bond energy (E) is a measure of bond strength in a chemical bond. ...

Overview

Endothermic, also known as endergonic, refers to a transformation in which a system receives heat from the surroundings:

Q > 0

When the transformation occurs at constant pressure:

∆H > 0

and constant volume:

∆U > 0

If the surroundings do not supply heat (e.g., when the system is adiabatic), an endothermic transformation leads to a decrease in the temperature of the system.^[1] In thermodynamics, an adiabatic process or an isocaloric process is a thermodynamic process in which no heat is transferred to or from the working fluid. ...

Endothermic processes

Some examples of endothermic processes are:^[2]

• Melting of ice
• Depressurising a pressure can

Implications for chemical reactions

Chemical endothermic reactions need heat to be performed. In a thermochemical reaction that is endothermic, the heat is placed on the reactants side (heat is necessary for and absorbed during the reaction).

Applications of endothermic processes

Endothermic materials in passive fire protection

Main article: Passive fire protection

Endothermic substances, both natural, e.g. gypsum, and synthetic, e.g. resin-based intumescents, are popular for use in heatshielding, ablation, materials in space physics, fireproofing, e.g. fire-resistive coatings for LPG vessels, and compartmentalisation of fire in buildings, which is the cornerstone of passive fire protection. Typically, the technological basis is the conversion of hydrates, or chemically bound water into vapour, or steam. Fire-resistance rated wall assembly with fire door, cable tray penetration and intumescent [1] cable coating. ... For other uses, see Gypsum (disambiguation). ... This article does not cite any references or sources. ... An intumescent is a substance which swells as a result of heat exposure, thus increasing in volume, and decreasing in density. ... Ablation is defined as the removal of material from the surface of an object by vaporization, chipping, or other erosive processes. ... Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. ... Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... 45 kg LPG cylinders Spherical Gas Container typically found in Refineries. ... In structures, such as land-based buildings, traffic tunnels, ships, aerospace vehicles, or submarines, compartmentalization is the fundamental basis and aim of passive fire protection. ... Hydrate is a term which means different things in inorganic chemistry and organic chemistry. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Steam (disambiguation). ...

See also

• Endergonic
  • Endergonic reaction
• Exergonic
  • Exergonic reaction

Endergonic means absorbing energy in the form of work. ... An endergonic reaction is a chemical reaction in which the change in free energy is positive. ... Look up exergonic in Wiktionary, the free dictionary. ... An exergonic reaction is a chemical reaction where the variation of free energy is negative. ...

References

External links

• Endothermic Definition - MSDS Hyper-Glossary
• School experiment