An energy diagram is a visual representation of the energy changes that occur during a chemical reaction. It shows the initial and final energy levels of the reactants and products, as well as the activation energy required for the reaction to proceed.
Activation energy refers to the minimum amount of energy required for a chemical reaction to occur. It's like the push needed to start climbing up that first hill on a roller coaster.
An exothermic reaction releases heat or thermal energy into its surroundings. It's like going down a steep drop on a roller coaster and feeling all that rush of excitement.
An endothermic reaction absorbs heat or thermal energy from its surroundings. It's like going up a hill on a roller coaster, needing extra input of external energy to climb higher.