18. Consider the decomposition of sulfur trioxide gas to sulfur dioxide gas and oxygen gas. Use the following data (at 25°C) to determine the temperature in °C at which standard-state equilibrium is reached for this reaction.
ΔHºf values (in kJ/mol): SO3(g), –396; SO2(g), −297; O2(g), 0
Sº values (in J/K•mol): SO3(g), 257; SO2(g), 248; O2(g), 205
(1) 272 °C (2) 198 °C (3) 448 °C (4) 786 °C (5) 912 °C
i know the answer is 786 but i cant find how to get there

Question

18.  Consider the decomposition of sulfur trioxide gas to sulfur dioxide gas and oxygen gas.  Use the following data (at 25°C) to determine the temperature in °C at which standard-state equilibrium is reached for this reaction.  
ΔHºf values (in kJ/mol): SO3(g),  –396; SO2(g), −297; O2(g), 0  
Sº values (in J/K•mol): SO3(g), 257; SO2(g), 248; O2(g), 205
	(1)  272 °C       (2)  198 °C       (3)  448 °C       (4)  786 °C       (5)  912 °C
i know the answer is 786 but i cant find how to get there

anonymous · Answer

i figured it out, in case anyone is interested you must balance the equation then plug in given numbers to get Hrxn of 198 and Srxn of .187 after you convert s to kJ from J then put H/S=k after you get that answer in kelvin subtract by 273 to arrive at the answer of 786 in celcius