Determining Spontaneity Using ΔH, ΔS, and ΔG:

Key:

- ΔH°: Enthalpy change

- ΔS°: Entropy change

- T: Temperature

- ΔG°: Gibbs free energy change

- Spontaneous: Reaction occurs without external input.

---

### Conditions for Spontaneity:

1. ΔH° = +

ΔS° = -

ΔG° = +

Spontaneity: Always non-spontaneous.

2. ΔH° = -

ΔS° = +

ΔG° = -

Spontaneity: Always spontaneous.

3. ΔH° = +

ΔS° = +

- If ΔG° = -, Spontaneity: Spontaneous at high T.

- If ΔG° = +, Spontaneity: Non-spontaneous at low T.

4. ΔH° = -

ΔS° = -

- If ΔG° = +, Spontaneity: Non-spontaneous at high T.

- If ΔG° = -, Spontaneity: Spontaneous at low T.