What occurs when Delta S is negative and Delta H is negative?

What occurs when Delta S is negative and Delta H is negative?

• A. The process is spontaneous at high temperatures
• B. The process is spontaneous at all temperatures
• C. The process is spontaneous at low temperatures
• D. The process is non-spontaneous at any temperature

Answer: (C)

When the change in entropy (Delta S) is negative and the change in enthalpy (Delta H) is also negative, the process exhibits specific thermodynamic characteristics. A negative Delta H indicates that the reaction is exothermic, meaning it releases heat. A negative Delta S suggests a decrease in randomness or disorder in the system. According to Gibbs Free Energy (G), which determines the spontaneity of a process, the relationship can be defined by the equation: G = Delta H - T * Delta S In this equation, T represents temperature in Kelvin. For the process to be spontaneous, G must be negative. Given that both Delta H is negative and Delta S is negative, the behavior of the Gibbs Free Energy depends on the temperature. As the temperature increases, the term T * Delta S becomes more negative. At lower temperatures, the negative Delta H (which favors spontaneity) outweighs the effect of the negative T * Delta S (which opposes spontaneity). Therefore, the process is spontaneous at low temperatures where the exothermic nature dominates. As temperature increases, the influence of the negative entropy becomes significant, leading to non-spontaneous behavior at higher temperatures. Thus, the correct conclusion is that the process is

When the change in entropy (Delta S) is negative and the change in enthalpy (Delta H) is also negative, the process exhibits specific thermodynamic characteristics. A negative Delta H indicates that the reaction is exothermic, meaning it releases heat. A negative Delta S suggests a decrease in randomness or disorder in the system.

According to Gibbs Free Energy (G), which determines the spontaneity of a process, the relationship can be defined by the equation:

G = Delta H - T * Delta S

In this equation, T represents temperature in Kelvin. For the process to be spontaneous, G must be negative. Given that both Delta H is negative and Delta S is negative, the behavior of the Gibbs Free Energy depends on the temperature. As the temperature increases, the term T * Delta S becomes more negative.

At lower temperatures, the negative Delta H (which favors spontaneity) outweighs the effect of the negative T * Delta S (which opposes spontaneity). Therefore, the process is spontaneous at low temperatures where the exothermic nature dominates. As temperature increases, the influence of the negative entropy becomes significant, leading to non-spontaneous behavior at higher temperatures.

Thus, the correct conclusion is that the process is