Explain why ethanol has a relatively low boiling point compared to giant covalent substances.

The combustion of ethanol in oxygen is an exothermic reaction. Which statement correctly describes the reaction profile for this exothermic reaction?

• A: The reactants are at a lower energy level than the products, and the overall energy change is represented by the difference in energy between reactants and products.
• B: The reactants are at a higher energy level than the products, and the overall energy change is represented by the difference in energy between reactants and products.
• C: The reactants are at a higher energy level than the products, and the overall energy change is represented by the energy difference between the reactants and the peak of the curve.
• D: The reactants are at a lower energy level than the products, and the overall energy change is represented by the energy difference between the reactants and the peak of the curve.

The balanced equation for the combustion of ethanol is: $C_2{H}_{5}OH+3O_2\to 2{CO}_2+3H_{2}O$

The molecules have the following structural bonds:

• Ethanol ($C_2{H}_{5}OH$): contains $1\times C-C$, $5\times C-H$, $1\times C-O$, and $1\times O-H$ bonds.
• Oxygen ($O_2$): contains $1\times O=O$ bond per molecule.
• Carbon dioxide (${CO}_2$): contains $2\times C=O$ bonds per molecule.
• Water ($H_{2}O$): contains $2\times O-H$ bonds per molecule.

The overall energy change of this exothermic reaction is $1276kJ/mol$.

The table below shows the bond energies for some of these bonds:

Calculate the bond energy of the $C-C$ bond ($X$).