Question

SO3(g) decomposes to produce SO2(g) and O2(g), as represented by

2SO3(g)⇄2SO2(g)+O2(g)               ΔH°=180kJ/molrxn

Under what temperature conditions will the reaction be thermodynamically favored: high temperatures, low temperatures, all temperatures, or no temperatures? Justify your answer in terms of the change in enthalpy and the change in entropy during the reaction.

Answer 1

$\Delta$G=$\Delta$H-T$\Delta$S.

For a reaction to be spontaneous, the $\Delta$G must be negative.

Therefore, the favorable conditions are a negative $\Delta$H value and a positive $\Delta$S value.

For the above reaction, $\Delta$H is positive.

Also, $\Delta$S is positive as two moles of gaseous reactants are giving three moles of gaseous products.

Therefore, to make the overall $\Delta$G value negative,high Temperatures are required.

Therefore, the correct answer is high temperatures.

Thank You!