Exothermic + Endothermic Reactions

• An exothermic reaction is a reaction that transfers energy to the surroundings, so the temperature of the surroundings increases
• An endothermic reaction is a reaction that takes in energy from the surroundings, so the temperature of the surroundings decreases
• A reaction (or enthalpy) profile diagram is a diagram, that shows the energy change during a chemical reaction
• 3 examples of exothermic reactions are combustion, neutralisation and oxidation
• 2 examples of endothermic reactions are thermal decomposition and citric acid + sodium hydrogen carbonate
• Endothermic - the energy of the products is higher than the reactants, so energy has been gained from the surroundings

  
• Exothermic - the energy of the products is lower than the reactants, so energy has been lost to the surroundings

  
• Endothermic - the energy of the products is higher than the reactants, so energy has been gained from the surroundings

  
• Hand-warmers and self heating cans use exothermic chemical reactions (they increase the temperature of their surroundings)
• Sports injury cold packs use endothermic reactions (they decrease the temperature of their surroundings)