Calculate Bond Energy for C25H52 Combustion Reaction

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Discussion Overview

The discussion revolves around calculating the bond energy for the combustion reaction of C25H52, focusing on the necessary bond types and energies involved in the reaction. Participants explore the theoretical framework for bond energy calculations in the context of a combustion reaction.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant presents a balanced combustion equation for C25H52 and attempts to calculate bond energies but expresses uncertainty about the structure of the hydrocarbon and the types of bonds present.
  • Another participant suggests that knowing the specific types of bonds is unnecessary, emphasizing that only the total bond energy is required.
  • A third participant identifies C25H52 as an alkane and clarifies that bond energy is not simply a sum of all bonds in the reaction but rather a property of individual bonds or molecules.
  • One participant seeks clarification on the assignment's requirements, indicating that they need to account for the energies involved in breaking and forming all bonds in the reaction to determine if it is exothermic or endothermic.
  • A later reply reiterates the assumption that C25H52 is an alkane, indicating a desire for clarity without further elaboration.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of knowing specific bond types for the calculation. While some agree on the classification of C25H52 as an alkane, the discussion remains unresolved regarding the method of calculating bond energy and the implications for the reaction's thermodynamics.

Contextual Notes

There is uncertainty regarding the specific structure of C25H52 and how it affects the bond energy calculations. Participants have not resolved the mathematical steps necessary for determining the total bond energy.

Who May Find This Useful

Students and educators involved in chemistry or chemical engineering, particularly those focusing on thermodynamics and reaction energetics.

k-rod AP 2010
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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.
 
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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.
 
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.

--
 
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.
 
As I already wrote - assume it is an alkane.

And I won't repeat it third time.
 
i wasnt sure what that meant, but i looked it up and that makes sense... srry bout that and thanks
 

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