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Forming a bond is a favorable/lower energy state for atoms to be in, so that energy is released. Consider the chart we looked at in 14A-- two atoms decreased in their energies as they became closer, the lowest energy being when they formed a bond; however, when they got any closer, the energy skyrocketed due to the repelling interaction of the two nuclei.
Jainam Shah 4I wrote:It is negative, because bonds are being formed and the rxn is exothermic. Forming bonds is more favorable, because it doesn't require an input of energy breaking bonds does.
The reaction being endothermic or exothermic in Thermochemistry is based on what is happening to the surroundings. To break bonds the reaction itself is absorbing heat, which is lowering the temperature of the surroundings therefore this is exothermic. When forming bonds the reaction will have to release heat and therefore the surroundings with absorb heat making it endothermic.
When you form a bond, you release energy. On the other hand, when you break bonds, you must add energy. This is because atoms/molecules are more stable when they are bonded together, so to break bonds you must add. When you form bonds, electrons typically go to lower, more stable orbitals, so it releases energy.
Leila_4E wrote:This confuses me too because its not like it gives off energy to create a bond, right? Unless it is saying it gives off energy to break a bond.
When the bond is formed, energy is given off to the surroundings.
When the bond is broken, energy is absorbed by the system.
It is really important to clarify transfer of energy in terms of the system and surroundings, or else it can be really confusing
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