Is exergonic the same as endothermic or exothermic?
1 Answer
Exergonic refer to changes in the Gibbs free energy. Exothermic and endothermic refer to changes in enthalpy.
Explanation:
Exothermic and endothermic refer to changes in enthalpy
"Exo" and "exer" mean "out of". "Endo" and "ender" mean "into".
For a given reaction, the change in Gibbs free energy is
We have four possibilities:
1.
The process is both exothermic and exergonic. It is always spontaneous.
2.
The process is both endothermic and endergonic. It is never spontaneous.
3.
This gives
At high temperatures,
An example is the endothermic decomposition of calcium carbonate.
CaCO₃(s) → CaO(s) + CO₂(g).
ΔS is positive because the reaction produces a gas from a solid. CaCO₃ is stable at room temperature but decomposes at high temperatures.
4.
This gives
At high temperatures,
An example is the exothermic synthesis of ammonia.
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
Increasing the temperature increases the yield of ammonia. But it drives the position of equilibrium to the left.