The bond energy for a \(C-H\) bond is about 413 \(\mathrm{kJ} / \mathrm{mol}\) in \(\mathrm{CH}_{4}\) but 380 \(\mathrm{kJ} / \mathrm{mol}\) in \(\mathrm{CHBr}_{3}\) . Although these values are relatively close in magnitude, they are different. Explain why they are different. Does the fact that the bond energy is lower in \(\mathrm{CHBr}_{3}\) make any sense? Why?

Bond energy is the amount of energy required to break a chemical bond between two atoms. It is affected by factors such as the type and size of atoms, the distance between them, and their neighboring atoms' influence.

CH₄ (methane) is a simple, symmetrical molecule with four hydrogen atoms bonded to a central carbon atom. The four C-H bonds in CH₄ are all single bonds with equal bond lengths and bond strengths.

CHBr₃ is called Bromoform, which contains one hydrogen atom and three bromine atoms bonded to a carbon atom. The molecule is more complex than CH₄, with different bond lengths and electronegativities between carbon and its bonded atoms.

The difference in bond energy between the C-H bond in CH₄ and CHBr₃ can be attributed mainly to the following factors: 1. Electronegativity difference: In CH₄, the carbon and hydrogen atoms have a small difference in electronegativity, causing a bond polarity. In CHBr₃, the carbon-bromine bond is even more polar due to the larger electronegativity difference between the atoms, which induces electron cloud distortion in the C-H bond, decreasing its strength. 2. Size and shielding effect: The bromine atoms in CHBr₃ are much larger than the hydrogen atoms in CH₄. As a result, the electron cloud in the C-H bond can experience more shielding from the large electron cloud of the bromine atoms, reducing the bond strength. 3. Steric effect: Due to the bulky size of bromine atoms, the bond strength of the C-H bond may be affected by the repulsive forces between the electron clouds of the hydrogen and bromine atoms. So steric effect can also contribute to a lower bond energy in CHBr₃ than in CH₄.

Yes, the lower bond energy of the C-H bond in CHBr₃ does make sense because of the factors mentioned above. The presence of larger, more electronegative bromine atoms nearby the C-H bond influences the bond strength by inducing electron cloud distortion, increasing the shielding effect, and causing steric repulsions. All these factors contribute to a weaker C-H bond in CHBr₃ compared to the C-H bond in CH₄.