Question about Calculating Bond Energies

In summary, the conversation was about calculating bond energies in C2H6 for a chemical equation. The student was given the bond energy for C-H bonds but not for C-C bonds. They were questioning whether the C-C bond energy can be ignored because it is not mentioned in the question. However, it was noted that elements do not have a bond energy of zero. The student provided a picture of the question, which was to calculate the change in H for C2H6. It was suggested that the C-C bond energy may cancel out in the calculation.
  • #1
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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  • #2
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
 
  • #3
Definitely not zero. Can you show whole question, perhaps C-C bond can be somehow ignored?
 
  • #4
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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  • #5
Too small for details, but I still think C-C bond energy cancels out.
 

Related to Question about Calculating Bond Energies

1. How is bond energy calculated?

Bond energy is calculated by subtracting the energy of the separated atoms from the energy of the bonded atoms. This difference in energy is known as the bond energy.

2. What factors affect bond energy?

The strength of a bond is influenced by the distance between the bonded atoms, the types of atoms involved, and the presence of any electron pairs or lone pairs of electrons. Generally, stronger bonds have shorter bond lengths and involve atoms with higher electronegativities.

3. Can bond energy be measured experimentally?

Yes, bond energies can be measured experimentally through techniques such as calorimetry, mass spectrometry, and infrared spectroscopy. These methods involve breaking bonds and measuring the amount of energy released or absorbed.

4. How is bond energy related to bond strength?

Bond energy and bond strength are directly proportional. This means that the higher the bond energy, the stronger the bond between the atoms. Bonds with high bond energies are more difficult to break, indicating a strong bond between the atoms.

5. What is the significance of bond energy in chemical reactions?

Bond energy is an important factor in determining the stability and reactivity of molecules. In a chemical reaction, the breaking of bonds requires energy while the formation of new bonds releases energy. The difference in bond energies between the reactants and products can determine whether a reaction is exothermic or endothermic.

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