Question

What happens when enthalpy (ΔH) is negative and entropy (ΔS) is positive?"

A) Reaction is spontaneous.
B) Reaction is non-spontaneous.
C) Depends on temperature.
D) Equilibrium is reached.

Answer 1

When enthalpy (ΔH) is negative and entropy (ΔS) is positive, the reaction is spontaneous at all temperatures, meaning it will occur without external influence.

Step-by-step explanation:

When enthalpy (ΔH) is negative and entropy (ΔS) is positive for a chemical reaction, it indicates that the reaction is exothermic and the disorder of the system increases. According to the second law of thermodynamics, processes that increase entropy tend to occur spontaneously. The free energy change (ΔG) for a process can be calculated using the formula ΔG = ΔH - TΔS, where T is the absolute temperature in Kelvin. Since both enthalpy change (ΔH) and the entropy term (-TΔS) will be negative (as T is always positive and ΔS is positive), ΔG will be negative, indicating that the reaction is spontaneous at all temperatures.