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Endothermic & Exothermic Reactions definitions

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  • Endothermic Reaction
    Heat-absorbing process where molecules gain energy, speed up, and may break bonds, often causing phase changes like melting or vaporization.
  • Exothermic Reaction
    Heat-releasing process where molecules lose energy, slow down, and form bonds, often resulting in condensation or freezing.
  • Thermal Energy
    Form of energy transferred as heat, influencing molecular motion and phase changes during chemical reactions.
  • Bond Breaking
    Process requiring energy input, leading to separation of atoms within molecules, common in heat-absorbing reactions.
  • Bond Formation
    Process where atoms join together, releasing energy, typical in heat-releasing reactions.
  • Phase Change
    Transition between states of matter, such as solid to liquid or liquid to gas, driven by energy absorption or release.
  • Fusion
    Transition from solid to liquid, requiring absorption of heat, also known as melting.
  • Vaporization
    Transition from liquid to gas, involving energy absorption to separate molecules.
  • Sublimation
    Direct transition from solid to gas, bypassing the liquid phase, requiring significant energy input.
  • Condensation
    Transition from gas to liquid, involving energy release as molecules come closer together.
  • Freezing
    Transition from liquid to solid, where molecules lose energy and arrange into a fixed structure.
  • Deposition
    Direct transition from gas to solid, skipping the liquid phase, accompanied by energy release.
  • Energy Diagram
    Graphical representation showing energy changes of reactants and products during a chemical reaction.
  • Enthalpy
    Measure of total heat content in a system, indicating energy absorbed or released during reactions.
  • Delta H
    Symbol representing the change in enthalpy, positive for heat absorption and negative for heat release.