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Thermodynamics vs. kinetics in chemical reactions
Thermodynamics dictates equilibrium (which says whether this reaction will
take place).
Kinetics involves the rate of the reaction
 | Kinetics is affected by catalysts. The rate of
the reaction involves the activation energy. Catalysts lower the
activation energy, which causes the reaction to speed up. |
 | Kinetics concerns the rate constant k (lower-case). |
Examples of thermodynamics-kinetics feuds :
 | Combustion (aka burning) of my physical chemistry book
is thermodynamically favored. Unfortunately, it is not favored
kinetically because the activation energy for the combustion reaction is too
high for the present conditions. One could always invest a little energy
in the form of a flame and start the reaction. The energy produced from
the combustion would supply the activation energy of the next reaction. |
 | The conversion of diamond into graphite is
thermodynamically favored (negative ΔG.) The speed of this reaction is
just too darn incredibly slow for a diamond to turn into graphite. |
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Thermodynamics |
Kinetics |
Determines |
Equilibrium (product vs. reactant) |
Speed of reaction |
Constant |
K (uppercase) = equilibrium constant |
k (lowercase) = rate constant |
Determined by |
ΔG (enthalpy and entropy) |
activation energy |
Buzzwords |
Entropy, enthalpy, Gibbs free energy, spontaneous, endo- and
exothermic, equilibrium |
Rate, speed, time, catalyst, enzyme, activation energy,
reaction order, first-order, second-order, rate-limiting step, bottleneck |
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