If ΔH is negative and ΔS is positive, what can be said about ΔG?

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Q: If ΔH is negative and ΔS is positive, what can be said about ΔG?

Solution: If ΔH is negative and ΔS is positive, ΔG will always be negative, indicating that the reaction is spontaneous at all temperatures.

Steps: 8

Step 1: Understand what ΔH means. ΔH is the change in enthalpy (heat content) of a reaction. If ΔH is negative, it means the reaction releases heat.
Step 2: Understand what ΔS means. ΔS is the change in entropy (disorder) of a reaction. If ΔS is positive, it means the disorder of the system increases.
Step 3: Know what ΔG means. ΔG is the change in Gibbs free energy, which helps determine if a reaction is spontaneous (can happen on its own).
Step 4: Use the Gibbs free energy equation: ΔG = ΔH - TΔS, where T is the temperature in Kelvin.
Step 5: Since ΔH is negative and ΔS is positive, the term -TΔS will also be negative (because T is always positive).
Step 6: When you combine a negative ΔH and a negative -TΔS, ΔG will be negative.
Step 7: A negative ΔG means the reaction is spontaneous, which means it can occur without needing extra energy.
Step 8: Therefore, if ΔH is negative and ΔS is positive, ΔG will always be negative at all temperatures.