Use the given average bond energy values to estimate ΔH for the following reaction in the gas phase.
Cl2 + F2 → 2FCl
DCl-Cl = 239 kJ/mol
DF-F = 154 kJ/mol
DF-Cl = 253 kJ/mol
The units expected here are simply "kJ". The implication is that the reaction coefficients refer to numbers of moles.