Energetics

• What is the basis for distinguishing between endothermic and exothermic reactions?

  Temperature change of the surroundings

  
• What type of reaction transfers energy to the surroundings, increasing the temperature of the surroundings?

  Exothermic reaction
• What are some examples of exothermic reactions?

  Combustion, oxidation, neutralization
• What are some everyday examples of exothermic reactions?

  Self-heating cans, hand warmers
• What type of reaction takes in energy from the surroundings, decreasing the temperature of the surroundings?

  Endothermic reaction
• What are some examples of endothermic reactions?

  Thermal decomposition, citric acid reaction
• What are some everyday examples of endothermic reactions?

  Sports injury packs
• What is the purpose of a reaction profile?

  To show relative energies of reactants and products
• Why do chemical reactions require a minimum amount of energy for the reacting particles to collide and react?

  Activation energy is required
• What does the arrow in a reaction profile represent?

  Overall energy change
• What is activation energy?

  Energy needed for a reaction to occur
• How is the overall energy change of a reaction calculated?

  Sum of energy to break - sum of energy released
• What is the difference between an exothermic and an endothermic reaction in terms of energy?

  Exothermic: energy released, Endothermic: energy absorbed

  
• What are the characteristics of exothermic and endothermic reactions?

  Exothermic:

  • Transfers energy to the surroundings
  • Increases the temperature of the surroundings
  • Examples: combustion, oxidation, neutralization

  Endothermic:

  • Takes in energy from the surroundings
  • Decreases the temperature of the surroundings
  • Examples: thermal decomposition, citric acid reaction

  
• What is the purpose of a reaction profile, and what does it show?

  A reaction profile shows the relative energies of reactants and products, the activation energy, and the overall energy change of a reaction. It is used to visualize the energy changes that occur during a chemical reaction.
• How is the overall energy change of a reaction calculated, and what is the difference between exothermic and endothermic reactions in terms of energy?

  The overall energy change is calculated by subtracting the sum of energy released from the sum of energy to break. Exothermic reactions release energy, while endothermic reactions absorb energy.