?

AP® Chemistry

Free Version

Upgrade subject to access all content

Moderate

Geometric Bond Dissociation

APCHEM-L9NXKK

Given ethene $(C_2H_4)$ and ethyne $(C_2H_2)$, which of the following would be expected to have a higher sum of all bond dissociation energies for the substance based on the following bond enthalpies?

Bond Bond Energy
$C-H \quad$ 413 kJ/mol
$C-C$ 347 kJ/mol
$C=C$ 614 kJ/mol
$C≡C$ 839 kJ/mol
A

Ethene because there are two more $C-H$ bonds that can be broken, requiring more overall energy.

B

Ethyne because the $C≡C$ bond is very short so it is the strongest and requires more overall energy to break it.

C

The two compounds will have comparable bond dissociation energies.

D

The bond energies of the two compounds cannot be directly compared due to the differences in structure.