Bond breaking and bond formation are respectively
- A. both exothermic
- B. both endothermic
- C. exothermic and endothermic
- D. endothermic and exothermic
Explanation
Energy must be supplied to pull bonded atoms apart, so breaking is endothermic, while forming a bond releases energy and is exothermic. Whether the overall reaction is exothermic depends on which total is larger, so a reaction releasing more energy in making new bonds than it spends breaking old ones is exothermic. This is the reasoning behind calculating enthalpy change from bond energies.
Related questions
Which of the following is an endothermic process?
A reaction mixture in a beaker becomes noticeably cold. This shows that the reaction is
The enthalpy of neutralisation of a strong acid by a strong alkali is almost constant at about minus 57 kJ per mole because
The dissolving of ammonium nitrate in water lowers the temperature of the solution, which means that
An energy profile diagram for an endothermic reaction shows