Heat of combustion and hydrogenation

[inaccensa]

I'm getting the following impression,

The higher the heat of combustion or greater the enthalpy of reaction (since this is an exothermic reaction) the higher the energy of the reactants and thus less stable.

Similarly for heats of hydrogenation, the less the heat of hydrogenation, the less energy of the reactants and more stable the product.

Do we follow these guidelines when we are comparing 2 reactions? Is this trend true for all reactions, since change in enthalpy, H =H (products) - H (reactants).

What are isometric hydrogen's?

---

Members don't see this ad.

 

[inaccensa]

anyone please?

 

[Omni]

I am as well confused with the combustion and hydrogenation. But this is what I have:
Heat of hydrogenation is the release of energy when pi bonds are converted to sigma. As a result, the greater the heat of hydrogenation, the greater the potential energy, and as a result, the less stable the molecule.
Heat of combustion works the same way, its the liberation of energy. greater the heat of combustion, lower the stability.

And as for your equation, I think that is right.