Heat of combustion of alkanols (1 Viewer)

[petermaniah198]

Can someone explain to me why heat of combustion increases as carbon chain length increases? I know fire sure that it is something to do with more moles of co2 being produced in the products, but not entirely sure as to the full reasoning. Pls help clarify this

 

[petermaniah198]

Bummpbumpb

 

[leehuan]

This is not important in the course.

However, whilst searching I found something quite interesting:
https://au.answers.yahoo.com/question/index?qid=20130505003719AAk9Kua


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Please refrain from unnecessarily bumping something you posted in the same day.

 

[piethepker]

I'm pretty sure its simply that as the carbon chains get longer, there are more bonds. Hence, when combustion occurs, there are more bonds to break, and as more bonds means more energy released (as energy is released when bonds are broken), the heat of combustion gets larger as the carbon chain increases.

 

[leehuan]

I'm pretty sure its simply that as the carbon chains get longer, there are more bonds. Hence, when combustion occurs, there are more bonds to break, and as more bonds means more energy released (as energy is released when bonds are broken), the heat of combustion gets larger as the carbon chain increases.

False

The reaction is exothermic because the energy released in forming the products is more than the energy required to break the bonds.

Conceptually, however, as that can be directly related to molecular weight there's reliability between your main idea and my link.

 

[Queenroot]

Usually because the molecule is getting heavier

 

[piethepker]

False

The reaction is exothermic because the energy released in forming the products is more than the energy required to break the bonds.

Conceptually, however, as that can be directly related to molecular weight there's reliability between your main idea and my link.

Ah your right! Opps.

 

[ragingcurry]

More carbon atoms means more bonds which means that there will be more dispersion forces and therefore more energy is required to break all the bonds.

Hope that helps