In 1774 Joseph Priestley prepared the element oxygen by heating mercury(II) oxide: HgO(s) → Hg(l) + ½O₂(g)
For this reaction, ΔH° = 90.84 kJ and ΔS° = 108 J/K. Which of the following statements is true?

Question

Quizplus · Accepted Answer

The spontaneity of the reaction is determined by the sign and magnitude of ΔG°, which can be calculated using the equation ΔG° = ΔH° - TΔS°. Since ΔH° is positive and ΔS° is positive, the sign of ΔG° depends on temperature. As temperature increases, the TΔS° term becomes more positive and can overcome the positive ΔH° term, leading to a less favorable ΔG°. Thus, the reaction is spontaneous only at high temperatures when the TΔS° term is large enough to make ΔG° negative.

In 1774 Joseph Priestley Prepared the Element Oxygen by Heating