what kind of reactions tend to be spontaneous? a. reactions that are exothermic b. reactions that decrease…
what kind of reactions tend to be spontaneous? a. reactions that are exothermic b. reactions that decrease in entropy c. reactions that increase in enthalpy d. reactions that are endothermic
Answer
Brief Explanations:
To determine which reactions are spontaneous, we analyze each option:
- Option A: Exothermic reactions release energy (ΔH < 0). Combined with entropy considerations (ΔS), using the Gibbs free energy equation ( \Delta G=\Delta H - T\Delta S ), exothermic reactions (negative ΔH) have a higher chance of being spontaneous (ΔG < 0), especially at moderate temperatures.
- Option B: A decrease in entropy (ΔS < 0) makes ( -T\Delta S ) positive. For a reaction to be spontaneous, ( \Delta G ) needs to be negative, so a decrease in entropy alone is not favorable for spontaneity.
- Option C: An increase in enthalpy (ΔH > 0) is endothermic and makes ( \Delta G ) more positive, less likely to be spontaneous.
- Option D: Endothermic reactions (ΔH > 0) absorb energy, making spontaneous reactions less likely as ( \Delta G ) is more positive.
So exothermic reactions (Option A) are more likely to be spontaneous.