# Calculate Bond Energy for C25H52 Combustion Reaction

• k-rod AP 2010
In summary, C25H52 reacts in a combustion reaction and the balanced equation is C25H52 + 38O2 = 25CO2 + 26H2O. To calculate bond energy, you only need to know the total bond energy and it is not necessary to know the types of bonds or bond energy of each bond. The structure of C25H52 can be assumed to be an alkane for the purposes of this calculation.
k-rod AP 2010

## Homework Statement

C25H52 reacts in a combustion reaction. Calculate Bond Energy

## 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.

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

## 1. What is bond energy?

Bond energy is the amount of energy required to break a chemical bond between two atoms. It is measured in kilojoules per mole (kJ/mol).

## 2. How do you calculate bond energy?

To calculate bond energy for a combustion reaction, you need to know the bond energies of all the bonds broken and formed during the reaction. You can find these values in a reference table. Then, use the equation: Bond energy = sum of bonds broken - sum of bonds formed.

## 3. What is the bond energy for a C-C bond?

The bond energy for a C-C bond is approximately 348 kJ/mol.

## 4. How does bond energy affect the energy released in a combustion reaction?

Bond energy plays a significant role in determining the energy released in a combustion reaction. The higher the bond energy, the more energy is required to break the bonds and the more energy is released when the bonds are formed. Therefore, a higher bond energy results in a more exothermic (energy-releasing) reaction.

## 5. Can bond energy be negative?

No, bond energy cannot be negative. It is always a positive value because energy is always required to break a bond.

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