Energetics

C3.2 Energetics

Summary Chemical reactions are accompanied by an energy change. A simple model involving the breaking and making of chemical bonds can be used to interpret and calculate the energy change. Underlying knowledge and understanding Learners should be familiar with exothermic and endothermic chemical reactions. Common misconceptions Learners commonly have the idea that energy is lost or used up. They do not grasp the idea that energy is transferred. Learners also wrongly think that energy

is released when bonds break and do not link this release of energy with the formation of bonds. They also may think for example that a candle burning is endothermic because heat is needed to initiate the reaction.