Final answer:
To calculate the standard enthalpy change (ΔH°) and determine the spontaneity of a reaction, we need specific information that is not provided in the question.
Step-by-step explanation:
To calculate the standard enthalpy change (ΔH°) for a reaction, we need the standard enthalpy of formation (ΔH°f) values for the reactants and products involved. Unfortunately, the specific reaction in the question is not provided, so we cannot calculate ΔH°. In order to determine the spontaneity of a reaction at a given temperature, we need to consider the change in entropy (ΔS°) and the temperature (T). If ΔS° is positive and T is high, the reaction is more likely to be spontaneous. However, without the specific values for ΔS° and T, we cannot determine the spontaneity of the reaction at 25°C.