Final answer:
A spontaneous reaction does not require Delta S to always be positive, as spontaneity is determined by Delta G being negative. Different combinations of Delta H and Delta S can lead to a negative Delta G, depending on the temperature of the system.
Step-by-step explanation:
For a spontaneous reaction to occur, it is not necessary for Delta S (the change in entropy) to always be positive. The spontaneity of a reaction depends on the change in free energy, denoted as Delta G. If Delta G is less than zero, the reaction is considered spontaneous. This condition means that the system is releasing free energy and moving towards a more stable state.
A spontaneous reaction can occur with either a positive or negative Delta S. It is the sign of Delta G that determines spontaneity. The relationship between Delta G, Delta H (enthalpy change), and Delta S is given by the equation ΔG = ΔH - TΔS, where T is the temperature in Kelvin. For a reaction to be spontaneous at a certain temperature, Delta G must be negative. This can occur in different scenarios:
- If Delta H is negative (exothermic reaction) and Delta S is positive, Delta G will be negative at all temperatures, indicating spontaneity.
- If Delta H is positive (endothermic reaction) and Delta S is negative, Delta G will be positive at all temperatures, and the reaction will not be spontaneous.
- If Delta H and Delta S are both negative or both positive, the spontaneity will depend on the temperature of the system.
Therefore, the correct answer to the question is False. A positive change in entropy is not a requirement for a reaction to be spontaneous.