energy profile diagram

• Energy Profile Diagram:

  • Shows the energy changes during a chemical reaction
  • Has a y-axis for energy and an x-axis for the progress of the reaction
  • Depicts how energy changes as reactants interact and become products
• Reactants to Products Transition:

  • Reactants must be dismantled before forming products
  • Bond breaking in reactants is endothermic, requiring energy
• Energy Profile Diagram Construction:

  • Reactants (e.g., hydrogen and oxygen) at one energy level
  • Bonds in reactants break, causing energy to increase
  • New bonds form in products, causing energy to decrease
• Key Terms:

  • Enthalpy change (ΔH): Energy level between reactants and products
  • Activation energy (Ea): Minimum energy for a reaction to occur
  • Represents the energy level between reactants and the highest point in the diagram
• Reverse Reaction Energy Profile:

  • Water (reactants) at an energy level
  • Hydrogen and oxygen (products) at another energy level
  • Bonds in water break, causing energy to rise before decreasing
• Energy Profile Diagram Characteristics:

  • Arrows indicate the direction of energy change
  • Upward arrow for endothermic reactions (products have higher energy)
  • Downward arrow for exothermic reactions (products have lower energy)
• Activation Energy in Reverse Reaction:

  • Activation energy is between reactants and the highest point in the diagram
  • Represents the minimum energy required for the reaction to occur
• Exam Tip:

  • In some exams, if an x-axis is provided in a question asking for an energy level diagram, it actually requires an energy profile diagram