CH4 (g) + N2 (g) ------> HCN (g) + NH3 (g) Delta Hf -74.9 0 135 -45.9 S 186.1 19

ID: 784446 • Letter: C

Question

CH4 (g) + N2 (g) ------> HCN (g) + NH3 (g)

Delta Hf -74.9 0 135 -45.9

S 186.1 191.5 201.7 193

a) Calculate the delta G for the above reaction at 25 degree C and state wether it is spontaneous as written

b) Calculate the Kp for the reaction at 25 degree C

c) If the reaction is not spontaneous as written at 25 degrees C calculate the tempature at which the reaction becomes spontaneous.

Please include steps for each.....

delta S for reaction = (193+201.7) - (186.1+191.5) = 17.1

delta Hf = (135-45.9) -(-74.9+0) = 164

delta G = delta Hf - T*delta S = 164 - (298*17.1) = -4931.8

as delta G i snegative so the reaction is spontaneous...

b)G = -RT ln(Kc)

and Kp = Kc*(RT)^(delta n) ,here delta n = 0 beacuse 2 gas moles react to form two gas moles

so Kp = Kc =exp(-G/RT) = exp(4931.8/8.31*298) = 7.32

c) reaction is spontaneous