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Endothermic & Exothermic Reactions definitions

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  • Endothermic Reaction
    A process that absorbs thermal energy, causing molecules to speed up and break bonds, often feeling cold to the touch.
  • Exothermic Reaction
    A process that releases thermal energy, causing molecules to slow down and form bonds, often feeling warm to the touch.
  • Thermal Energy
    The energy absorbed or released during chemical reactions, affecting molecular motion and phase changes.
  • Phase Change
    A transition between different states of matter, such as solid, liquid, and gas, influenced by thermal energy.
  • Fusion
    The process of a solid absorbing heat to become a liquid, also known as melting.
  • Vaporization
    The process of a liquid absorbing heat to become a gas.
  • Sublimation
    The transition of a solid directly into a gas without passing through the liquid phase.
  • Condensation
    The process of a gas releasing heat to become a liquid.
  • Freezing
    The process of a liquid releasing heat to become a solid.
  • Deposition
    The transition of a gas directly into a solid without passing through the liquid phase.
  • Energy Diagram
    A graphical representation showing the energy changes during a chemical reaction.
  • Enthalpy
    A measure of heat change in a reaction, positive for endothermic and negative for exothermic processes.
  • Delta H
    The symbol representing the change in enthalpy during a chemical reaction.
  • Reactants
    The starting substances in a chemical reaction, typically at a higher energy level in exothermic reactions.
  • Products
    The substances formed in a chemical reaction, typically at a higher energy level in endothermic reactions.