Exothermic and Endothermic Reactions

• What is meant by an exothermic reaction?

  It is a reaction that transfers energy from the reacting molecules to the surroundings, increasing the temperature of the surroundings.
• What is meant by an endothermic reaction?

  It is a reaction that takes in energy from the surroundings, decreasing the temperature of the surroundings.
• What are the key characteristics of exothermic and endothermic reactions?

  • Exothermic reactions:
  • Transfer energy to surroundings
  • Surroundings get hotter
  • Endothermic reactions:
  • Take in energy from surroundings
  • Surroundings get colder
• What is the significance of energy profile diagrams in chemical reactions?

  • Represent energy changes in reactions
  • Show energy of reactants vs. products
  • Indicate energy released or absorbed
• How do energy profiles for exothermic reactions differ from those for endothermic reactions?

  Exothermic profiles show lower energy products, while endothermic profiles show higher energy products.
• What is activation energy?

  The minimum amount of energy that particles must have in order to react.
• How is activation energy represented on an energy profile diagram?

  • From the reactants to the peak of the curve
  • Indicates the energy required for the reaction to occur
• What is the relationship between particle collisions and activation energy?

  Particles must collide with enough energy to overcome activation energy for a reaction to occur.
• What are some practical applications of exothermic reactions?

  • Hand-warmers
  • Self-heating cans for food or drink