⚗️ Energy Profile Diagrams

IGCSE Chemistry — Exothermic & Endothermic Reactions

Energy Parameters
Reactant Energy200 kJ
Product Energy100 kJ
Activation Energy (Ea)80 kJ
Calculated Values
Reactant Energy
200 kJ
Product Energy
100 kJ
ΔH (enthalpy change)
−100 kJ
Activation Energy
80 kJ
Ea with catalyst
— kJ
Reaction Type
Exothermic
Key Concepts
Exothermic (ΔH < 0): Products have less energy than reactants. Energy is released to surroundings — temperature increases.
Activation Energy (Ea): Minimum energy needed for reactant particles to collide successfully and start the reaction.
Catalyst: Provides an alternative reaction pathway with lower Ea. Does NOT change ΔH — same reactants and products.