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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: _cheers on February 23, 2007, 04:29:25 PM

Title: unimolecular and bimolecular
Post by: _cheers on February 23, 2007, 04:29:25 PM

In doing some problems on elementary steps and rate laws....

2NO -> N₂0₂
2H₂ -> 4H
N₂0₂ + H -> N₂0 + HO
2HO + 2H -> 2H₂0
H + N₂0 -> HO + N₂

over= 2NO + 2H₂ -> 2H₂0 + N₂

question: why is 1) bimolecular when 2) is not and why is the rate law squared in 1 and not 2, 4?

probably a simple answer, but I just started reading this ...

thanks!

Title: Re: unimolecular and bimolecular
Post by: Kelvin on February 23, 2007, 04:58:29 PM

I think the second elementary step can be reduced to H2 --> 2H.

Title: Re: unimolecular and bimolecular
Post by: vhpk on February 24, 2007, 05:09:07 AM

I think (2) is bimolecular because there is a shock between 2 H₂.
I think the rate law squared in (1) maybe because (1) is a slow stage