endothermic/exothermic

• We learned that if a reaction involves only bond breaking, it's endothermic, and if it involves only bond forming, it's exothermic
• In the current video, we are exploring more reactions and focusing on bond energy
• For example, the reaction of hydrogen reacting with oxygen to form water involves both bond forming and bond breaking
• To determine if a reaction is endothermic or exothermic, we compare the total energy required for bond breaking with the total energy released for bond forming
• The formula to calculate this energy change is: ΔH = Bonds broken - Bonds formed
• Representing reactions in structural formulas helps identify the bonds that need to be broken and formed
• In the reaction of hydrogen with oxygen to form water, we need to break two hydrogen-hydrogen bonds and one oxygen-oxygen double bond, while forming four O-H bonds
• Calculating the energy change involves summing the energy required to break all bonds and subtracting the energy released when bonds are formed
• For this specific reaction, the total energy change is -482 kJ/mol, indicating it is exothermic
• The formula ΔH = Bonds broken - Bonds formed helps determine if a reaction is endothermic or exothermic
• In chemical reactions involving both bond breaking and bond forming, the total energy change reveals if the reaction is endothermic or exothermic
• The energy absorbed for bond breaking compared to the energy released for bond forming determines if a reaction is endothermic or exothermic
• In exam questions, understanding bond breaking and forming is crucial to explain why a reaction is endothermic or exothermic
• Identifying the bonds formed and broken is essential for explaining the energy change in a reaction
• In the reverse reaction of an exothermic reaction, the energy change is the same magnitude but with the opposite sign, making it endothermic