[mleftover]

I have been staring and working at this problem for quite a while, and can't figure out how to arrive at the answer in the back of the text. I am convinced I'm missing something small but extremely significant... most likely I'm missing something huge and extremely significant

The problem gives the rate constant (at 25^oC for the elementary gas phase reaction N₂O₄ 2NO₂ is 4.8x10⁴ s^-1. It says to use the data in the appendix to determine the rate constant at 25^oC for the reverse reaction: 2NO₂ N₂O₄.

I have the following equations:
K^o_c=K^o_p(RTC^o/P^o)^{- :delta: n/mol}
K^o_p=exp(- :delta: G^o/RT)
k₁/k_-1=K_c=K^o_c(C^o) ^{:delta: n/mol}

And going to the appendix, I have calculated  :delta: G^o=4.73x10³.

So I figure all I have to do is substitute one equation into another and plug in some numbers....?

I am looking for k_-1, so:

k_-1=k₁/[exp(- :delta: G^o/RT)(RTC^o/P^o)^{- :delta: n/mol} (C^o) ^{:delta: n/mol}]
= 4.8x10⁴/[exp(-4.73x10³/0.083145(298.15)) (0.083145(298.15))^-1(1)¹)
= 8.73x10⁸⁸

The back of the book says I should have 8.0x10⁶!


I'd appreciate any points towards the right direction  !!

[Borek]

No idea what went wrong, but obvious thing to do is to thoroughly check units. That's brute force method that may help locate some simple mistake either in derivation or in calculations.