Energetics & electrochemistry · HL
Gibbs Energy Calculator (HL)
HL tool. Entropy is entered in J mol⁻¹ K⁻¹; enthalpy and Gibbs energy are displayed in kJ mol⁻¹.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
ΔG° = ΔH° − TΔS°
ΔG° = −RT ln K
| Symbol | Meaning |
|---|---|
| T | Absolute temperature in K. |
| R | 8.314462618 J mol⁻¹ K⁻¹. |
When to use this calculator
A negative ΔG° corresponds to K > 1 under the standard-state relationship. Spontaneity under non-standard conditions depends on composition as well as ΔG°.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- TΔS° = 298.15 × (-198) = -59033.7 J mol⁻¹ = -59.0337 kJ mol⁻¹
- ΔG° = ΔH° − TΔS° = -92.4 − (-59.0337) = -33.3663 kJ mol⁻¹
-33.3663 kJ mol⁻¹
Common mistakes
- Convert ΔS° from J to kJ before combining with ΔH° in kJ.