[chehemi123]

Hello,

I am desperate...
I got the following task:

Calculate from the following data Kp for the reaction equation: 2SO₂ + O₂ <--> 2SO₃ at 600 °C and at 700 °C.

Data:

for SO₂:
S⁰ : 249 J·mol^-1·K^-1
c_p : 46,5 J·mol^-1·K^-1

for O₂:
S⁰ : 205 J·mol^-1·K^-1
c_p : 31,9 J·mol^-1·K^-1

for SO₃:
S⁰ : 257 J·mol^-1·K^-1
c_p : 59,0 J·mol^-1·K^-1


I have no idea how to start, hopefully you can help me...

[discodermolide]

Have a look here,
http://www.chemguide.co.uk/physical/equilibria/kp.html
and try to answer your own question.
Then read the Forum Rules.

[outman]

Hello,

I am desperate...
I got the following task:

Calculate from the following data Kp for the reaction equation: 2SO₂ + O₂ <--> 2SO₃ at 600 °C and at 700 °C.

Data:

for SO₂:
S⁰ : 249 J·mol^-1·K^-1
c_p : 46,5 J·mol^-1·K^-1

for O₂:
S⁰ : 205 J·mol^-1·K^-1
c_p : 31,9 J·mol^-1·K^-1

for SO₃:
S⁰ : 257 J·mol^-1·K^-1
c_p : 59,0 J·mol^-1·K^-1


I have no idea how to start, hopefully you can help me...

1. △S     
2. △H
3. △G 
4. △G=RTlnK

[chehemi123]

1. △S   should be: 2·257 - (205+2·249) = -189 ??

or how is △S calculated??

and what is K in 4. :  △G=RTlnK

2.  △H = H(products) - H (reagents) ...is this right??

[chehemi123]

i found △H = -198KJ/mol
 
△S = ΣS°(products) - ΣS°(reagents)            right?

how can I calculate S°(products)/S°(reagents) at 873K ? I think Cp is needed....

[outman]

△S is right

C_p is need for  △H。  △H can be got  by  △C_pdT ？

K is K^Θ   

u need transform K^Θ to K_p

[chehemi123]

hey guys...

im still working at that problem..

i think ive found an interesting formula (attachment)!

but im not quite sure how to solve the integral. and what is ΔCp (T) ??

i hope you can help me... it is so difficult, i think