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 See Table 17.1 in Tro, Fridgen and Shaw.

(a) PbS (s) + Mg (s) → Mg (s) + Pb (s); ∆H = 66 kJ; ∆S = -9 J/K

(b) 2 SO2 (g) + O2 (g) → 2 SO3 (g); ∆H = -197.8 kJ; ∆S = -188.1 J/K

(c) 2 N2O (g) + O2 (g) → 4 NO (g); ∆H = 199.5 kJ; ∆S = 198.2 J/K

(d) 2 C8H18 (l) + 25 O2 (g) → 16 CO2 (g) + 18 H2O (g); ∆H = -10139 kJ; ∆S = 977 J/K

Answer 1

If ∆G is negative reaction will be spontaneous