. The Haber process for the synthesis of ammonia is kinetically and thermodynamically controlled.
N2(g) + 3 H2(g) f 2 NH3(g)
for the reaction above: al-P = -92 kJ, AS° = -199 J K-I
a) Calculate aG° from the thermodynamic data and comment on the spontaneity of the reaction at room temperature.
b) Calculate the equilibrium constant at room temperature.
c) At what temperature does AG° become zero? What does this mean in regards to the temperature at which this reaction can be carried out at?
d) The rate of reaction at room temperature is very low. Give an explanation for this fact.
e) Propose a way to shift the rate of the reaction and also shift equilibrium towards products.
Refer to the system PCI3(g) + Cl)2(g f PCI5(g). To an empty 15.0-L cylinder, 0.500 mol of gaseous PC15 are added and allowed to reach equilibrium. The concentration of PCI3 is found to be 0.0220 M. Assume a temperature of 375 K.
a) How many mol of PCI5 remain at equilibrium?
b) Write the equilibrium constant expression for the above reaction.
c) Determine the value of K.
d) Determine the value of Kp for this same system at the same temperature
3 answers
@Jay.
a. dGo = dHo - TdSo
b. dGo = -RTlnK. Substitute and solve for K.
c. Set dGo = 0 and solve for T
d. The activation energy is high.
Post your work if you get stuck.