# What is the equation for the reaction that represents the mean "C-F" bond energy in carbon tetrafluoride?

May 25, 2017

The equation is $\frac{1}{4} \text{CF"_4"(g)" → 1/4"C(g)" + "F(g)}$.

#### Explanation:

The bond dissociation enthalpy is the energy needed to break one mole of the bonds to give separated atoms, with everything being in the gaseous state.

Tetrafluoromethane, ${\text{CF}}_{4}$, contains four identical $\text{C-F}$ bonds.

However, if you take ${\text{CF}}_{4}$ to pieces one fluorine at a time, you will have to supply a different amount of energy to break each bond.

Each time you break a $\text{C-F}$ bond, the environment of those left behind changes, and the strength of a bond is affected by what else is around it.

Thus, you would need to break the bonds in 0.25 mol of ${\text{CF}}_{4}$ (1 mol of $\text{C-F}$ bonds), and the total energy involved would then be the mean bond energy.

The thermochemical equation representing this process is

$\frac{1}{4} \text{CF"_4"(g)" → 1/4"C(g)" + "F(g)}$.