Left Diagram (Chemical Reactions That Absorb Energy – Endothermic Reaction)

1. Reactants – The starting point on the energy scale (left side, bottom of the curve).
2. Activation Energy – The vertical arrow leading up to the peak (indicating the energy needed to reach the transition state).
3. Transition State – The peak of the curve.
4. Energy Absorbed – The difference between the reactants’ and products’ energy levels, showing an increase (from reactants to products).
5. Products – The end point after the reaction, at a higher energy level than the reactants.

Right Diagram (Chemical Reactions That Release Energy – Exothermic Reaction)

1. Reactants – The starting point on the energy scale (left side, bottom of the curve).
2. Activation Energy – The vertical arrow leading up to the peak (indicating the energy needed to reach the transition state).
3. Transition State – The peak of the curve.
4. Energy Released – The difference between the reactants’ and products’ energy levels, showing a decrease (from reactants to products).
5. Products – The end point after the reaction, at a lower energy level than the reactants.