endothermic and exothermic reactions

• What is meant by an exothermic reaction?

  An exothermic reaction transfers energy from the reacting molecules to the surroundings.
• How does an exothermic reaction affect the temperature of the surroundings?

  The temperature of the surroundings increases, making them hotter.
• What is a common example of an exothermic reaction?

  Combustion, such as wood burning.
• Name two other examples of exothermic reactions.

  Certain oxidation reactions and neutralization reactions.
• What do scientists use to represent energy changes in reactions?

  Energy profile diagrams.
• In an exothermic energy profile diagram, what can be observed about the energy of the products compared to the reactants?

  The products have less energy than the reactants.
• What are two practical applications of exothermic reactions?

  Hand-warmers and self-heating cans.
• What does the difference in energy between the reactants and products in an exothermic reaction indicate?

  It indicates the amount of energy released to the surroundings.
• What is meant by an endothermic reaction?

  An endothermic reaction takes in energy from its surroundings.
• How does an endothermic reaction affect the temperature of the surroundings?

  The temperature of the surroundings decreases, making them colder.
• What is a good example of an endothermic reaction?

  Thermal decomposition.
• In an endothermic energy profile diagram, what can be observed about the energy of the products compared to the reactants?

  The products have more energy than the reactants.
• What does the difference in energy between the reactants and products in an endothermic reaction indicate?

  It indicates the amount of energy taken in by the reaction.
• What do exothermic and endothermic reactions have in common regarding their energy profiles?

  Both have energy that rises to a peak, known as activation energy.
• What is activation energy?

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

  It is represented as the energy from the reactants to the peak of the curve.
• How does the activation energy differ between exothermic and endothermic reactions in energy profiles?

  The activation energy is shown as a peak in both exothermic and endothermic energy profiles.
• What are the key features of exothermic reactions?

  • Transfer energy to surroundings
  • Increase temperature of surroundings
  • Examples: combustion, oxidation, neutralization
  • Energy profile shows products with less energy than reactants
• What are the key features of endothermic reactions?

  • Absorb energy from surroundings
  • Decrease temperature of surroundings
  • Example: thermal decomposition
  • Energy profile shows products with more energy than reactants
• What is the significance of activation energy in chemical reactions?

  • Minimum energy required for particles to collide and react
  • Represented as the peak in energy profile diagrams