Calculate Bond Energy for C25H52 Combustion Reaction

[k-rod AP 2010]

Homework Statement

C₂₅H₅₂ reacts in a combustion reaction. Calculate Bond Energy

Homework Equations

The Attempt at a Solution

the balanced equation would be
C₂₅H₅₂ + 38O₂ = 25CO₂ + 26H₂O
38 o=o bonds + 50 c-o bonds + 52 h-o bonds
(38*495 KJ) + (50*-358 KJ) + (52*-467 KJ)

I have gotten this far but i don't know what the structure of the C₂₅H₅₂ is so i don't know how many c-c, c-h, or h-h bonds there may be. Could anyone help me figure it out.

 

[zhermes]

You don't need to know the types of bonds or the bond energy of each type of bond. You just need to know the total bond energy.

 

[Borek]

Judging from the formula, C₂₅H₅₂ is just an alkane.

Bond energy is not calculated as a sum of all bonds in all compounds in the reaction equation. Bond energy is either a property of a single bond, or of a molecule.

--

 

[k-rod AP 2010]

maybe i called what i am looking for by the wrong name, but our teacher wants us to add up all the energies it takes to either break or make all of the bonds in the entire reaction, then depending on whether that final number is positive or negative, tell whether it is exo or endothermic.

thats y i need help deciphering the structure of the hydrocarbon, i need to add up the energies to break all of its bonds, but i don't know what's bonded to what.

 

[Borek]

As I already wrote - assume it is an alkane.

And I won't repeat it third time.

 

[k-rod AP 2010]

i wasnt sure what that meant, but i looked it up and that makes sense... srry bout that and thanks