C5-Energy changed

• What is conserved in chemical reactions?

  Energy is conserved
• What happens to the temperature during an endothermic reaction?

  The temperature falls
• What is an example of an endothermic reaction?

  Citric acid + sodium hydrogencarbonate
• What is a use of endothermic reactions?

  Some sports injury packs
• What happens to the temperature during an exothermic reaction?

  The temperature rises
• What is an example of an exothermic reaction?

  Combustion
• What is a use of exothermic reactions?

  Self-heating cans and hand warmers
• What are the characteristics of endothermic and exothermic reactions?

  • Endothermic:
  • Takes in energy
  • Temperature falls
  • Example: Citric acid + sodium hydrogencarbonate
  • Use: Sports injury packs
  • Exothermic:
  • Transfers energy
  • Temperature rises
  • Example: Combustion
  • Use: Self-heating cans and hand warmers
• What is activation energy?

  Minimum amount of energy that reactants need to react
• What do reaction profiles for endothermic and exothermic reactions illustrate?

  • Endothermic:
  • Energy absorbed
  • Reactants have lower energy than products
  • Exothermic:
  • Energy released
  • Reactants have higher energy than products