what does it mean to have a fractional order of reaction. like [H2]]1/2, does this means 1/2 moles of bromine is reacting with one mole of hydrogen?

Edited July 21, 200817 yr by Phi for All
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[math] reaction rate = constant * [H2][br2]^{1/2} [/math]

 

It means that you take the concentration of H2, multiply it by the square root of the concentration of Br2, and (optionally, but commonly) multiply it by a constant.

 

The reaction is (probably):

[ce]H2 + Br2 --> 2 HBr [/ce]

So, you can see that 1 mole of H2 react with 1 mole of Br2, to form 2 moles of HBr.

 

p.s. if you just have a question, you can just ask... no need to post other things (like about rubber or Kr)... some people ask, some give answers... but it's not a market where you must sell something before you can buy something

Reaction orders are just what you measure. They are not under any obligation to be nice simple numbers.

The molecularity of a reaction is another matter, a bimolecular reaction really must involve the reaction of two molecules.