Answer
See below
Work Step by Step
(a) $Δ_{r}$G° at 80.0 °C = +0.14 kJ/mol-rxn
$Δ_{r}$G° at 110.0 °C = −0.12 kJ/mol-rxn
Rhombic sulfur is more stable than monoclinic
sulfur at 80 °C, but the reverse is true at 110 °C.
(b) T = 370 K or about 96 °C. This is the temperature at which the two forms are at equilibrium
under standard conditions.
