Question about Calculating Bond Energies

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    Bond Energies
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In calculating bond energies for C2H6, the focus is on the C-H bonds, which are valued at 414 kJ/mol, with six present in the molecule. The discussion raises the question of whether the C-C bond energy should be included in the calculations, especially since no specific value is provided for it. Participants clarify that the C-C bond energy is not zero and cannot be ignored, as it contributes to the overall energy change. The need for a complete question context is emphasized to better understand the calculations involved. Ultimately, the C-C bond energy is significant and should be factored into the calculation of the change in enthalpy (ΔH).
Lori

Homework Statement


Part of a chemical equation, but i had to calculate the bond energies in C2H6,

Homework Equations


im given that C-H bonds are 414 kj/mol[/B]

The Attempt at a Solution


and that i know there are 6 of these based on the lewis structure, but how come i don't have to include C-C bond energy? I wasnt given the bond energy for this. C2H6 was part of a chemical equation in which i had to calculate the bond energy for to find change in H[/B]
 
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Is it because if the elements are the same, then there is no bond energy? Cause i know that elements have 0 heat of formation
 
Definitely not zero. Can you show whole question, perhaps C-C bond can be somehow ignored?
 
Borek said:
Definitely not zero. Can you show whole question, perhaps C-C bond can be somehow ignored?
Hopefully you can see the question in the pic. It's question 16. Calculate change in H.
IMG1227841956.jpg
 

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Too small for details, but I still think C-C bond energy cancels out.
 
Thread 'Confusion regarding a chemical kinetics problem'

Thread 'Confusion regarding a chemical kinetics problem'

TL;DR Summary: cannot find out error in solution proposed. [![question with rate laws][1]][1] Now the rate law for the reaction (i.e reaction rate) can be written as: $$ R= k[N_2O_5] $$ my main question is, WHAT is this reaction equal to? what I mean here is, whether $$k[N_2O_5]= -d[N_2O_5]/dt$$ or is it $$k[N_2O_5]= -1/2 \frac{d}{dt} [N_2O_5] $$ ? The latter seems to be more apt, as the reaction rate must be -1/2 (disappearance rate of N2O5), which adheres to the stoichiometry of the...
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