Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. Bond: C≡C C-C H-I C-I C-H D (kJ/mol): 839 348 299 240 413
A)+160
B)-160
C)-217
D)-63
E)+63

Question

Using the table of average bond energies below, the ΔH for the reaction is ________ kJ.  Bond: C≡C C-C H-I C-I C-H D (kJ/mol): 839 348 299 240 413
A)+160 
B)-160 
C)-217 
D)-63 
E)+63

Quizplus · Accepted Answer

The ΔH for the reaction can be calculated using the following formula:

ΔH = Σ(bond energies of reactants) - Σ(bond energies of products)

The balanced chemical equation for the reaction is not given, so let's assume it involves the breaking of one C≡C bond and the formation of one C-I bond and one H-I bond.

Reactants:
C≡C (1 bond) : 839 kJ/mol
H-I (1 bond) : 299 kJ/mol

Products:
C-I (1 bond) : 240 kJ/mol
C-H (1 bond) : 413 kJ/mol

ΔH = (839 kJ/mol + 299 kJ/mol) - (240 kJ/mol + 413 kJ/mol) = -217 kJ/mol

Therefore, the answer is C, -217.

Using the Table of Average Bond Energies Below, the ΔH