GCSE Combined Science (AQA)

622 videos | 38 hours

Reaction Profiles

Please subscribe to watch this video.

This, and all other videos, are included in our premium subscriptions.

Premium accounts get access to all videos.

Energy changes Exothermic and endothermic reactions

Reaction Profiles

9:45 Reaction Profiles
Spec 4.5.1.2
Previous Activation Energy Next Elastic & Inelastic Deformations
  • Reaction profiles are graphs that show the change in energy during a chemical reaction.
  • The x-axis refers to the progress of the reaction over time, and the y-axis refers to the energy.
  • Reaction profiles can be used to visualize the energy of reactants, the energy during the reaction, and the energy of products.
  • Reaction profiles are also called energy level diagrams.
  • They can be drawn for both exothermic and endothermic reactions, which transfer energy in different directions.
  • The first flat section shows the relative energy of reactants.
  • The curved line shows the energy as the reaction proceeds, indicating an increase and then a decrease in energy.
  • The top of the hump shows the activation energy needed for the reaction.
  • The flat section on the right shows the energy levels of the products relative to the reactants.
  • In exothermic reactions, the products line is lower than the reactants line, indicating energy is released.
  • In endothermic reactions, the products line is higher, indicating energy is absorbed.
  • The difference between reactants and products levels represents the overall energy change.
  • For exothermic reactions, energy is transferred to the surroundings.
  • For endothermic reactions, energy is taken in from the surroundings.
  • Reaction profiles can be labeled with the actual chemicals involved in the reaction.
  • In exams, you may be asked to draw and label reaction profiles for exothermic or endothermic reactions.
  • Steps to draw a reaction profile include drawing lines for reactants and products, indicating activation energy, and labeling energy changes.

Please subscribe to access these revision notes.

This, and all other video notes, are included in our premium subscriptions.

Premium accounts get access to all videos and revision notes.