Chemical Forums
Specialty Chemistry Forums => Chemical Engineering Forum => Topic started by: Gerard on November 28, 2006, 10:15:49 AM
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we are asked to derived the rate equation of
A+2B=R
yes i derived the other half which is
-ln{(M-2XA)/M(1-XA)}=CA0(M-2)KT
but then we are asked what if M=2 this is where our problem arises..
what if M=2
what will happen to the equation???further more we are also asked what are the thermodynaimc quantities that can predict whether a reaction is reversible or irreversible???
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A + 2B => R
I assume XA refers to XA - the conversion of A.
This is the rate equation: Rate = - d[A]/dt = K[A][ B ]2
- d[A]/dt = - (d/dt)([A]0(1 - XA) = [A]0dXA/dt
From the stoichiometric ratio, [ B ]0XB = 2 [A]0XA
[ B ] = [ B ]0(1 - XB)
K[ A ][ B ]2 = K[A]0(1 - XA)([ B ]0-[ B ]0XB)2 = K[A]0(1 - XA)([ B ]0 - 2[A]0XA)2
[A]0dXA/dt = K[A]0(1 - XA)([ B ]0 - 2[A]0XA)2
dXA/dt = K(1 - XA)([ B ]0 - 2[A]0XA)2
Solving the above ODE will yield the correct reaction profile.
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further more we are also asked what are the thermodynaimc quantities that can predict whether a reaction is reversible or irreversible???
dG = dH - T.dS
if dG = 0, then your reaction is reversible
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further more we are also asked what are the thermodynaimc quantities that can predict whether a reaction is reversible or irreversible???
dG = dH - T.dS
if dG = 0, then your reaction is reversible
i feel ashamed of myself! i did not took acount the gibbs free energy what ever happened to my chemical thermodynamics
thank you
a lot!