For a reaction with a negative ΔH and a positive ΔS, what can be said about the

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Question: For a reaction with a negative ΔH and a positive ΔS, what can be said about the spontaneity at high temperatures?

Options:

Correct Answer: The reaction is spontaneous.

Solution:

A negative ΔH and a positive ΔS indicate that the reaction is spontaneous at high temperatures, as ΔG will be negative.

For a reaction with a negative ΔH and a positive ΔS, what can be said about the spontaneity at high temperatures?

For a reaction with a negative ΔH and a positive ΔS, what can be said about the spontaneity at high temperatures?

Step 1: Understand what ΔH means. A negative ΔH means the reaction releases heat (exothermic).
Step 2: Understand what ΔS means. A positive ΔS means the disorder of the system increases.
Step 3: Know that spontaneity of a reaction can be determined using the Gibbs free energy equation: ΔG = ΔH - TΔS.
Step 4: Recognize that for a reaction to be spontaneous, ΔG must be negative.
Step 5: Since ΔH is negative and ΔS is positive, as temperature (T) increases, the term TΔS becomes larger and more positive.
Step 6: At high temperatures, the positive TΔS term will outweigh the negative ΔH, making ΔG negative.
Step 7: Therefore, the reaction is spontaneous at high temperatures.

Gibbs Free Energy – The relationship between enthalpy (ΔH), entropy (ΔS), and spontaneity of a reaction is described by the Gibbs free energy equation: ΔG = ΔH - TΔS.
Spontaneity of Reactions – A reaction is spontaneous when ΔG is negative, which can occur when ΔH is negative and ΔS is positive, especially at high temperatures.
Temperature's Role – At high temperatures, the TΔS term becomes significant, making it more likely for ΔG to be negative if ΔS is positive.