endothermic

(adjective)

A chemical reaction that absorbs heat energy from its surroundings.

Related Terms

  • exothermic
  • homolysis
  • enthalpy

(adjective)

of a chemical reaction that absorbs heat energy from its surroundings

Related Terms

  • exothermic
  • homolysis
  • enthalpy

(adjective)

A description of a chemical reaction that absorbs heat energy from its surroundings.

Related Terms

  • exothermic
  • homolysis
  • enthalpy

Examples of endothermic in the following topics:

  • Exothermic and Endothermic Processes

    • In thermodynamics, these two types of reactions are classified as exothermic or endothermic, respectively.
    • As such, the change in enthalpy for an endothermic reaction is always positive.
    • In order to melt the ice cube, heat is required, so the process is endothermic.
    • In an endothermic reaction, the products are higher in energy than the reactants.
    • Paul Andersen explains how heat can be absorbed in endothermic or released in exothermic reactions.
  • Thermochemical Equations

    • The sign of the $\Delta H$ value indicates whether or not the system is endothermic or exothermic.
    • In an endothermic system, the $\Delta H$ value is positive, so the reaction absorbs heat into the system.
    • Notice that in an endothermic reaction like the one depicted above, we can think of heat as being a reactant, just like A and B.
  • Energy Changes in Chemical Reactions

    • Endothermic reactions, on the other hand, absorb heat and/or light from their surroundings.
    • For example, decomposition reactions are usually endothermic.
    • In endothermic reactions, the products have more enthalpy than the reactants.
    • Thus, an endothermic reaction is said to have a positive enthalpy of reaction.
    • Significant heat energy is needed for this reaction to proceed, so the reaction is endothermic.
  • Heat of Solution

    • The breaking of bonds within the solute, such as the electrostatic attraction between two ions (endothermic)
    • The breaking of intermolecular attractive forces within the solvent, such as hydrogen bonds (endothermic)
    • If more energy is used in breaking bonds than is released upon solute-solvent bond formation, then the overall process is endothermic, and ∆Hsol is positive.
    • Dissolution of sodium chloride (table salt) in water is endothermic.
    • Dissolution of sodium chloride in water is endothermic.
  • Changes in Temperature

    • Reactions with positive enthalpies—those that absorb heat from their surroundings—are known as endothermic.
    • Endothermic reactions, on the other hand, will be shifted towards product formation as heat is removed from the reaction's surrounding environment.
  • Le Chatelier's Principle

    • Recall that for an endothermic reaction, heat is absorbed in the reaction, and the value of $\Delta H$ is positive.
    • Thus, for an endothermic reaction, we can picture heat as being a reactant:
    • Conversely, lowering the temperature on an endothermic reaction will shift the equilibrium to the left, since lowering the temperature in this case is equivalent to removing a reactant.
    • Our heat of reaction is positive, so this reaction is endothermic.
    • Since this reaction is endothermic, heat is a reactant.
  • Solid to Gas Phase Transition

    • It is an endothermic phase transition that occurs at temperatures and pressures below a substance's triple point (the temperature and pressure at which all three phases coexist) in its phase diagram.
    • The process of sublimation requires additional energy and is therefore an endothermic change.
  • Bond Enthalpy

    • The change ($\Delta H$) is positive in endothermic reactions because the products of the reaction have a greater enthalpy than the reactants, and heat is absorbed by the system from its surroundings.
    • In other words, breaking a bond is an endothermic process, while the formation of bonds is exothermic.
  • Solutions and Heats of Hydration

    • The first reaction (ionization) is always endothermic; it takes a lot of work to break up an ionic crystal lattice into its component ions.
    • As often happens for a quantity that is the sum of two large terms having opposite signs, the overall dissolution process can be either endothermic or exothermic.
    • An endothermic process, on the other hand, would show Hsolution as positive, and it would be higher in energy than the starting solute/solvent enthalpies.
  • Reaction Rates and Kinetics

    • The potential energy of a reacting system changes as the reaction progresses.The overall change may be exothermic ( energy is released ) or endothermic ( energy must be added ), and there is usually an activation energy requirement as well.
Subjects
  • Accounting
  • Algebra
  • Art History
  • Biology
  • Business
  • Calculus
  • Chemistry
  • Communications
  • Economics
  • Finance
  • Management
  • Marketing
  • Microbiology
  • Physics
  • Physiology
  • Political Science
  • Psychology
  • Sociology
  • Statistics
  • U.S. History
  • World History
  • Writing

Except where noted, content and user contributions on this site are licensed under CC BY-SA 4.0 with attribution required.