Gbelow which temperature does the following reaction change from being spontaneous to non-spontaneous? 2 hno3 (aq) + no (g) → 3 no2 (g) + h2o (l) δhº = +136.5 kj; δsº = +287.5 j/k below which temperature does the following reaction change from being spontaneous to non-spontaneous? 2 hno3 (aq) + no (g) → 3 no2 (g) + h2o (l) δhº = +136.5 kj; δsº = +287.5 j/k 475 k 39.2 k 151 k this reaction is nonspontaneous at all temperatures. this reaction is spontaneous at all temperatures.

Below 475 K the reaction changes from being spontaneous to non-spontaneous.

Explanation:

Let's consider the following reaction.

2 HNO₃(aq) + NO(g) → 3 NO₂(g) + H₂O(l)

The spontaneity of the reaction is given by the standard Gibbs free energy (ΔG°). When ΔG° > 0 the reaction is non-spontaneous and when ΔG° < 0 the reaction is spontaneous. ΔG° is related to the standard enthalpy (ΔHº) and the standard entropy (ΔSº) using the following expression.

ΔG° = ΔHº - T.ΔSº

The reaction will change from spontaneous to non-spontaneous when ΔG° = 0. Then,

ΔHº - T.ΔSº = 0

ΔHº = T.ΔSº

T = ΔHº/ΔSº = (136.5 × 10³ J)/(287.5 J/K) = 475 K

d

explanation:

answerlinnaeus;