Questions: Consider these qualitative observations describing a reaction and then answer the following questions: "A spontaneous reaction occurs in a solution within a flask. Upon touching the flask, it feels hot and becomes progressively warmer as the reaction continues" - Is the flask a part of the system or a part of the surroundings? - From these qualitative observations or by deduction using the Gibbs Free Energy equation, can you infer anything about the ΔH of this reaction? - From these qualitative observations or by deduction using the Gibbs Free Energy equation, can you infer anything about the ΔS of this reaction?

Solution Steps

The system refers to the specific part of the universe that is being studied, while the surroundings include everything else outside the system. In this scenario, the reaction occurs within the solution inside the flask. Therefore, the flask itself is not part of the system but rather part of the surroundings.

The observation states that the flask feels hot and becomes progressively warmer as the reaction continues. This indicates that heat is being released from the system to the surroundings. Since the reaction releases heat, it is exothermic. In thermodynamic terms, an exothermic reaction has a negative enthalpy change, $\Delta \mathrm{H} < 0$.

The reaction is described as spontaneous, which means it occurs without external intervention. The spontaneity of a reaction is determined by the Gibbs Free Energy equation: \[ \Delta G = \Delta H - T \Delta S \] For a reaction to be spontaneous, $\Delta G$ must be negative. Given that $\Delta \mathrm{H}$ is negative (exothermic reaction), and knowing that the reaction is spontaneous, we can infer that the term $-T \Delta S$ must be sufficiently negative to ensure $\Delta G < 0$. This implies that $\Delta \mathrm{S}$, the change in entropy, is likely positive, as a positive $\Delta \mathrm{S}$ would contribute to making $\Delta G$ more negative.

Final Answer