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il postino
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- Homework Statement
- For the reaction 2NO2 <---> 2NO + O2
It is known to reach equilibrium at a total pressure of 1 atm.
And it is known that the ratio pNO / pNO2 = 0.872 at 700K
and the ratio pNO / pNO2 = 2.5 at 800K.
Calculate the enthalpy of reaction between 700 and 800 K
- Relevant Equations
- Van´t Hoff
Hi all
Knowing that ##kp## is:
##k_p=\frac{pO_2.(pNO)^2}{(pNO_2)^2}##
And knowing these relationships between the partial pressures, I obtained:
At 700 K:
##pNO = 0.872.pNO2##
##k_p=pO_2.(0.872)^2##
At 800 K:
##pNO = 2.5.pNO2##
##k_p=pO_2.(2.5)^2##
Furthermore it is known that ##pNO + pNO + PO2 = 1 atm##
We also know that:
##\Delta H=\frac{-ln(\frac{kp2}{kp1})}{1/T2 - 1/T1}##
I honestly don't know how to continue.
Could you guide me?
Thank you very much
Knowing that ##kp## is:
##k_p=\frac{pO_2.(pNO)^2}{(pNO_2)^2}##
And knowing these relationships between the partial pressures, I obtained:
At 700 K:
##pNO = 0.872.pNO2##
##k_p=pO_2.(0.872)^2##
At 800 K:
##pNO = 2.5.pNO2##
##k_p=pO_2.(2.5)^2##
Furthermore it is known that ##pNO + pNO + PO2 = 1 atm##
We also know that:
##\Delta H=\frac{-ln(\frac{kp2}{kp1})}{1/T2 - 1/T1}##
I honestly don't know how to continue.
Could you guide me?
Thank you very much