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Jun30-04, 10:06 AM
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Activation Energy

Quote Quote by mrjeffy321
is there a way to tell the activation energy for a reaction mathmatically just based on what the reaction is, or what it contains? or do you just have to know what it is, based on looking off a table or some other way of finding that data.

lets say I have a hypothetical reaction:
X + Y -> XY

is there any way I could figure out before hand what the activation energy would be, would the type of reaction make a diference?
(for example synthesis, single/double replacement, combustion, decomposition,...)
Given X + Y --> XY, it is as hard to know k and A as it is to know E(a). In fact, the intuitive path would be that a knowledge of A and E(a) can tell you what k is.

E(a) is simply the energy of the highest point along the reaction co-ordinate. The exact value of E(a) can be determined though complex Qunatum Mechanical calculations...though there may be some pattern that is exhibited that depends on the type of reaction.

Here are some of the factors that E(a) depends on :
- geometry of the molecules
- bonds strengths of all bonds
- the number of bonds of each type that are broken/formed
- medium/solvent