Under what conditions will a reaction be spontaneous according to the values of Delta H and S?

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A chemical reaction is considered spontaneous when it can proceed without needing to be driven by external influences. The spontaneity of a reaction can be evaluated using the Gibbs free energy equation:

[ \Delta G = \Delta H - T\Delta S ]

where ( \Delta G ) is the change in Gibbs free energy, ( \Delta H ) is the change in enthalpy, ( T ) is the temperature in Kelvin, and ( \Delta S ) is the change in entropy.

For a reaction to be spontaneous, ( \Delta G ) needs to be negative.

  1. When ( \Delta H ) is negative, it indicates that the reaction is exothermic, meaning it releases heat. This generally favors spontaneity as the system loses energy.

  2. When ( \Delta S ) is positive, it reflects an increase in disorder or randomness in the system. Increased disorder also favors spontaneity because it contributes positively to the overall free energy change and allows for more configurations of the system.

Combining these two conditions, when ( \Delta H ) is negative and ( \Delta S ) is positive, both factors work together to ensure that the reaction is spontaneous. The heat released

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