bond energies

• What is the main focus of energy transfer in chemical reactions?

  Making and breaking bonds
• What must be supplied to break existing bonds?

  Energy
• What type of process is bond breaking?

  Endothermic process
• What happens when new bonds are formed?

  Energy is released
• What is bond formation classified as?

  Exothermic
• What distinguishes endothermic and exothermic reactions?

  • Endothermic: Energy to break bonds > Energy released
  • Exothermic: Energy released > Energy to break bonds
• What is bond energy?

  Energy associated with a chemical bond
• How does bond energy vary?

  It varies slightly by compound
• How can known bond energies be used in reactions?

  To calculate overall energy change
• What is the formula for overall energy change?

  Energy required to break bonds - Energy released by forming bonds
• What does a positive energy change indicate?

  Endothermic reaction
• What does a negative energy change indicate?

  Exothermic reaction
• How do you calculate the energy change for a reaction?

  1. Calculate energy to break bonds in reactants
  2. Calculate energy released by forming bonds in products
  3. Overall energy change = Energy to break - Energy released
• What is the significance of practicing bond energy calculations?

  • Helps understand energy changes in reactions
  • Essential for solving exam questions
  • Builds confidence in chemistry concepts