Study the potential energy diagram below. All reactions, even those that in the end release energy, require energy to begin. This addition of energy is called the activation energy. Once the activation energy has been added, a very unstable state is reached. This is called the activated complex. After the activated complex has been formed, the energy level decreases and the product is formed. If the energy level of the products is higher than that of the reactants, the reaction is said to be endothermic, that is, the reaction absorbed energy from the surroundings. If the energy level of the products is lower than that of the reactants, the reaction is said to be exothermic, that is, the reaction released energy to the surroundings.
Use the diagram above to match the label with the correct term.
1. ΔHr
2. activation energy
3. products
4. activated complex
5. reactants
Click here for the answers:
1.E, 2.C, 3.D, 4.A, 5.B