What is an exothermic reaction in terms of bond breaking and bond formation? [duplicate]








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[Why change in enthalpy is negative?](/questions/72768/why-change-in-enthalpy-is-negative)

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Nitrogen + Hydrogen -> Ammonia 
This reaction has a $\Delta H$ of -93kJ


This reaction is exothermic. Explain what it means in terms of bond breaking and bond formation


I know an exothermic reaction produced heat to the surrounding. 


**Energy graph for exothermic reactions**


![graph](https://bam.files.bbci.co.uk/bam/live/content/zrhj6v4/large)


It shows that reactants have higher energy. Enthalpy change (∆H) is probably negative because when we calculate we say *ΔH = Hproducts – Hreactants* then we get a negative number.


When I google I find that exothermic reactions are bond formation reactions. How is an exorthermic reaction bond formation. Does it have any ting to do with enthalpy change? Do we also have bond breaking in exothermic reactions.




Exothermic reactions are those reactions in which heat is evolved. If we are breaking a bond we need to energy to break it so those are endothermic reactions. But when a bond gets formed energy gets liberated those are known as exothermic reactions.


In the formation of ammonia three nitrogen - hydrogen bonds are formed which results in the form of loss of energy.


In the formation of bonds energy is released as they are getting stabilised due to bond formation so atoms used to release energy. The amount of energy released is dependent on various factors like electronegativity, electron affinity and various other factors.


This is a general trend. I don't know if there are exceptions as well please tell me if there are so so even I can know.


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