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  2. Activation energy - Wikipedia

    en.wikipedia.org/wiki/Activation_energy

    In the Arrhenius model of reaction rates, activation energy is the minimum amount of energy that must be available to reactants for a chemical reaction to occur. [1] The activation energy (Ea) of a reaction is measured in kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). [2] Activation energy can be thought of as the magnitude ...

  3. Chemical reaction - Wikipedia

    en.wikipedia.org/wiki/Chemical_reaction

    A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. [1] When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. Classically, chemical reactions encompass changes that only involve the positions ...

  4. Collision theory - Wikipedia

    en.wikipedia.org/wiki/Collision_theory

    Collision theory. Reaction rate tends to increase with concentration phenomenon explained by collision theory. Collision theory is a principle of chemistry used to predict the rates of chemical reactions. It states that when suitable particles of the reactant hit each other with the correct orientation, only a certain amount of collisions ...

  5. Enzyme - Wikipedia

    en.wikipedia.org/wiki/Enzyme

    At the maximum reaction rate (V max) of the enzyme, all the enzyme active sites are bound to substrate, and the amount of ES complex is the same as the total amount of enzyme. [1]: 8.4 V max is only one of several important kinetic parameters. The amount of substrate needed to achieve a given rate of reaction is also important.

  6. Active site - Wikipedia

    en.wikipedia.org/wiki/Active_site

    The active site consists of amino acid residues that form temporary bonds with the substrate, the binding site, and residues that catalyse a reaction of that substrate, the catalytic site. Although the active site occupies only ~10–20% of the volume of an enzyme, [1]: 19 it is the most important part as it directly catalyzes the chemical ...

  7. Enzyme catalysis - Wikipedia

    en.wikipedia.org/wiki/Enzyme_catalysis

    Enzyme catalysis is the increase in the rate of a process by an "enzyme", a biological molecule. Most enzymes are proteins, and most such processes are chemical reactions. Within the enzyme, generally catalysis occurs at a localized site, called the active site. Most enzymes are made predominantly of proteins, either a single protein chain or ...

  8. Lewis acid catalysis - Wikipedia

    en.wikipedia.org/wiki/Lewis_Acid_Catalysis

    Lewis acid catalysis. In Lewis acid catalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc ...

  9. Activation - Wikipedia

    en.wikipedia.org/wiki/Activation

    The energy of activation [1] specifies the amount of free energy the reactants must possess (in addition to their rest energy) in order to initiate their conversion into corresponding products—that is, in order to reach the transition state for the reaction. The energy needed for activation can be quite small, and often it is provided by the ...