Reaction profiles

• What is the difference between exothermic and endothermic reactions?

  Exothermic reactions transfer energy to the surroundings, while endothermic reactions take in energy.
• How does the temperature of the surroundings change during an exothermic reaction?

  The temperature of the surroundings increases during an exothermic reaction.
• What happens to the temperature of the surroundings during an endothermic reaction?

  The temperature of the surroundings decreases during an endothermic reaction.
• What is a reaction profile?

  • A chart showing how the energy of reactants and products changes during a reaction.
  • It illustrates the energy levels of reactants and products.
  • It indicates whether a reaction is exothermic or endothermic.
• What does an energy level diagram show?

  An energy level diagram shows the energy in the reactants and products, and the difference in energy between them.
• What does a downward arrow in a reaction profile indicate?

  A downward arrow indicates that energy is given out in an exothermic reaction.
• What does an upward arrow in a reaction profile indicate?

  An upward arrow indicates that energy is taken in during an endothermic reaction.
• What is activation energy?

  Activation energy is the minimum amount of energy that colliding particles must have for them to react.
• How is activation energy represented in a reaction profile?

  Activation energy is shown as a 'hump' in the line of a reaction profile.
• How can you tell from a reaction profile that a reaction is exothermic?

  In an exothermic reaction profile, the overall change is negative, indicating that products have less energy than reactants.
• How can you tell from a reaction profile that a reaction is endothermic?

  In an endothermic reaction profile, the overall change is positive, indicating that products have more energy than reactants.
• What are the characteristics of exothermic and endothermic reactions in terms of energy changes?

  Exothermic reactions:

  • Energy is released to the surroundings.
  • Temperature of surroundings increases.
  • Overall energy change is negative.

  
  

  Endothermic reactions:

  • Energy is absorbed from the surroundings.
  • Temperature of surroundings decreases.
  • Overall energy change is positive.