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  2. Rate equation - Wikipedia

    en.wikipedia.org/wiki/Rate_equation

    Rate equation. In chemistry, the rate equation (also known as the rate law or empirical differential rate equation) is an empirical differential mathematical expression for the reaction rate of a given reaction in terms of concentrations of chemical species and constant parameters (normally rate coefficients and partial orders of reaction) only ...

  3. SN2 reaction - Wikipedia

    en.wikipedia.org/wiki/SN2_reaction

    Note that the attacking group attacks from the backside of the leaving group. Bimolecular nucleophilic substitution(SN2) is a type of reaction mechanismthat is common in organic chemistry. In the SN2 reaction, a strong nucleophileforms a new bond to an sp3-hybridised carbon atom via a backside attack, all while the leaving groupdetaches from ...

  4. Phase transition - Wikipedia

    en.wikipedia.org/wiki/Phase_transition

    In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma.

  5. Rate-determining step - Wikipedia

    en.wikipedia.org/wiki/Rate-determining_step

    The second step with OH − is much faster, so the overall rate is independent of the concentration of OH −. In contrast, the alkaline hydrolysis of methyl bromide (CH 3 Br) is a bimolecular nucleophilic substitution (S N 2) reaction in a single bimolecular step. Its rate law is second-order: r = k[R−Br][OH −].

  6. Chemical kinetics - Wikipedia

    en.wikipedia.org/wiki/Chemical_kinetics

    After van 't Hoff, chemical kinetics deals with the experimental determination of reaction rates from which rate laws and rate constants are derived. Relatively simple rate laws exist for zero order reactions (for which reaction rates are independent of concentration), first order reactions, and second order reactions, and can be derived for ...

  7. Entropy (order and disorder) - Wikipedia

    en.wikipedia.org/wiki/Entropy_(order_and_disorder)

    A measure of disorder in the universe or of the unavailability of the energy in a system to do work. [7] Entropy and disorder also have associations with equilibrium. [8] Technically, entropy, from this perspective, is defined as a thermodynamic property which serves as a measure of how close a system is to equilibrium—that is, to perfect ...

  8. Desorption - Wikipedia

    en.wikipedia.org/wiki/Desorption

    This is because second order is re-combinative desorption and with a larger initial coverage there is a higher probability the two particles will find each other and recombine into the desorption product. An example of second order desorption, n = 2, is when two hydrogen atoms on the surface desorb and form a gaseous H 2 molecule. There is also ...

  9. Bond order - Wikipedia

    en.wikipedia.org/wiki/Bond_order

    Bond order. In chemistry, bond order is a formal measure of the multiplicity of a covalent bond between two atoms. As introduced by Linus Pauling, bond order is defined as the difference between the numbers of electron pairs in bonding and antibonding molecular orbitals . Bond order gives a rough indication of the stability of a bond.