Question

When 2 crystalline solid barium hydroxide octahydrate and crystalline solid ammonium nitrate are mixed in a beaker at room temperature, a spontaneous reaction occurs. the temperature of the beaker contents rapidly falls to below 0º

c. use this information to decide whether the reaction is exothermic or endothermic and what the signs of δh and δs are?

Answer 1

It is endothermic reaction ΔH>0 (sign is +).
Because it is spontaneous reaction ΔG<0 (Gibbs free energy)
ΔG=ΔH-TΔS, so must be TΔS>ΔH and ΔS>0 (sign +).