The bond enthalpy of the O-H bond in a water molecule is approximately 464 kJ/mol. Bond enthalpy is a measure of the energy required to break a bond between two atoms, and it is an indication of the bond strength. A higher bond enthalpy means that more energy is required to break the bond, which implies that the bond is stronger. In the case of the O-H bond in water, the relatively high bond enthalpy of 464 kJ/mol indicates that it is a strong bond.