I'm having trouble understanding the definition of bond energy. My textbook defines it as the energy required to break 1 mole of the bond in the gas phase. I don't understand what it means to break 1 mole of a bond. Cl2 (g) ---> 2 Cl(g) Bond energy = 243 kJ. Since 1 mole of Cl2 is 1.2*1024 molecules, does this mean bond energy is the total energy required to break 1.2*1024 Cl-Cl bonds?