Exothermic Reaction

[MedPR]

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I think I have this memorized, but I want to make sure my explanation (to myself) is correct and won't lead me astray if this concept ever slips out of my rote memory.

Exothermic reactions result in the formation of products that are more stable than the reactants.

This is because bond breaking is endothermic, while bond forming is exothermic. So when you break a bond, say you absorb 500kJ of energy. If your formed bond is more stable than your broken bond, that means your formed bond requires less energy since it's a favorable process and will happen with very little effort by the system or the atoms doing the bonding. This means that of the 500kJ you absorbed, you will only have to use, say, 200kJ. That 300kJ has to go somewhere, per conservation of energy, so the excess 300kJ is just released as heat. Thus, exothermic.

Good? Bad?

 

[theseeker4]

I think I have this memorized, but I want to make sure my explanation (to myself) is correct and won't lead me astray if this concept ever slips out of my rote memory.

Exothermic reactions result in the formation of products that are more stable than the reactants.

This is because bond breaking is endothermic, while bond forming is exothermic. So when you break a bond, say you absorb 500kJ of energy. If your formed bond is more stable than your broken bond, that means your formed bond requires less energy since it's a favorable process and will happen with very little effort by the system or the atoms doing the bonding. This means that of the 500kJ you absorbed, you will only have to use, say, 200kJ. That 300kJ has to go somewhere, per conservation of energy, so the excess 300kJ is just released as heat. Thus, exothermic.

Good? Bad?

Sounds good to me 👍

 

[ljc]

You can also look at it in terms of a reaction coordinate diagram.

Because the reaction is exothermic, the activation energy of the forward reaction is less than the reverse reaction. This means the forward reaction will happen easier than the reverse reaction, which means it is less volatile in its lower energy state (the lower right portion), thus more stable.

 

[Temperature101]

You can also look at it in terms of a reaction coordinate diagram.

Because the reaction is exothermic, the activation energy of the forward reaction is less than the reverse reaction. This means the forward reaction will happen easier than the reverse reaction, which means it is less volatile in its lower energy state (the lower right portion), thus more stable.

Great explanation...