Dissociation constant as function of T,p.

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Homework Statement


For given general reaction 2A<->A2 the affinity constant is known k(T)=1.7 10-4 mol/cm3 (t=18 C) Find dissociation (constant) level in normal pressure.

Homework Equations


So i solved it - found the general solution for dissociation constant.
alpha=1/(sqrt(1+4k))
Now i have some quaestions,So first of all where do i factor in the pressure?
Like this alpha=1/(sqrt(1+4 p k(T))) and if yes what kind of units would be correct to use?

More importantly If i need to calculate the dissociation constant for the same reaction but only in different temperature, what should i do then ?

Looking forward to hearing from you guys!

The Attempt at a Solution

 

Answers and Replies

  • #2
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PTotal = ∑Pi, where Pi are the partial pressures of all species present. Conversely, mole fraction x PTotal is the partial pressure of a selected species. Units obvious enough to you with that information?
 
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PTotal = ∑Pi, where Pi are the partial pressures of all species present. Conversely, mole fraction x PTotal is the partial pressure of a selected species. Units obvious enough to you with that information?
yes, i think units are clear now ,thanks :)

But still,not clear what to do with different temperature i know that k(t)=Exp(a),where a is function form chemical potential maybe its possible to calculate in this way. but its seems irrational.
 
  • #4
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You need enthalpy and heat capacity data (or estimates) for the reaction to examine temperature dependence.
 
  • #5
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You need enthalpy and heat capacity data (or estimates) for the reaction to examine temperature dependence.
I got it!
it is possible to get relation by using reaction heat
Q=RT^2 d/dT (ln K)
 

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