Question

Classify each of the following reactions as one of these four types:
• spontaneous at all temperatures
• not spontaneous at any temperature
• spontaneous below a certain temperature but not above
• spontaneous above a certain temperature but not below

(a) KClO3 (s) + S (s) ® KCl (s) + SO3 (g); ΔH = -435 kJ; ΔS = 164 J/K
(b) C2H5OH (g) ® C2H4 (g) + H2O (g); ΔH = 45.5 kJ; ΔS = 125.7 J/K
(c) 2 NO (g) + O2 (g) ® 2 NO2 (g); ΔH = -115.4 kJ; ΔS = -146.5 J/K
(d) PbS (s) + Mg (s) ® MgS (s) + Pb (s); ΔH = 66 kJ; ΔS = -9 J/K