At which temperature range would the following reaction be spontaneous?

2NH4NO3(s) -- 2N2(g) + 4H2O(g) + O2(g)

ΔH = -236 kJ/mol
ΔS = 46 J/mol K
A. The reaction is spontaneous at all temperatures.
B. The reaction is never spontaneous.
C. at temperatures above 5130 K
D. at temperatures below 5130 K

Question

At which temperature range would the following reaction be spontaneous?

2NH4NO3(s) --> 2N2(g) + 4H2O(g) + O2(g)

ΔH = -236 kJ/mol 
ΔS = 46 J/mol K
 		A.	The reaction is spontaneous at all temperatures.
 		B.	The reaction is never spontaneous.
 		C.	at temperatures above 5130 K
 		D.	at temperatures below 5130 K

vera_ewing · Answer

@dtan5457

dtan5457 · Answer

If you calculate the gibbs free energy, and it's negative. It is spontaneous at all temperatures. But calculate it first.

vera_ewing · Answer

How do I calculate it?

dtan5457 · Answer

attachment

dtan5457 · Answer

your already given entropy and enthalpy change

vera_ewing · Answer

Ohh so the answer is C right??

dtan5457 · Answer

so just plug in a number smaller than 5130 and one that's bigger than 5130, see which is negative.

vera_ewing · Answer

@JFraser Please help!

dtan5457 · Answer

Did you not understand this one?

jfraser · Answer

to find the "tipping point" temperature, plug in zero for $\Delta G$ and solve for T in the equation
$$\Delta G = \Delta H - T* \Delta S$$so that$$T = \frac{\Delta H - \Delta G}{\Delta S}$$