Bond energy is defined as which of the following?

Bond energy is defined as which of the following?

• A. The energy required to break 1 mole of a particular bond in 1 mole of gaseous molecules
• B. The energy released when a bond is formed
• C. The energy change when a reaction occurs at constant temperature
• D. The energy required to ionize an atom

Answer: (A)

Bond energy measures how strong a bond is by the energy required to break that bond. It is defined as the energy needed to break one mole of a specific bond in gaseous molecules, producing separated atoms in the gas phase. This endothermic value is specific to a particular bond type and to the gas phase, since breaking bonds in condensed phases or across different environments changes the energy involved. The energy released when a bond forms is the negative of this quantity, not the energy to break it. The energy change of a reaction at a given temperature is an overall enthalpy change, not a bond-specific breaking energy, and ionization energy refers to removing an electron from an atom, not breaking a covalent bond.

Bond energy measures how strong a bond is by the energy required to break that bond. It is defined as the energy needed to break one mole of a specific bond in gaseous molecules, producing separated atoms in the gas phase. This endothermic value is specific to a particular bond type and to the gas phase, since breaking bonds in condensed phases or across different environments changes the energy involved. The energy released when a bond forms is the negative of this quantity, not the energy to break it. The energy change of a reaction at a given temperature is an overall enthalpy change, not a bond-specific breaking energy, and ionization energy refers to removing an electron from an atom, not breaking a covalent bond.