An endothermic reaction is a chemical reaction that absorbs energy from the surroundings, usually in the form of heat (and sometimes light or electricity).
Key Features of Endothermic Reactions
- Energy Absorption
- The energy of the products is higher than that of the reactants.
- Extra energy is taken in to break bonds, making the surroundings lose heat.
- Temperature Change
- The surroundings become colder because heat is absorbed.
- Example: A beaker feels cool during an endothermic reaction.
- Energy Profile
- On an energy diagram, the curve goes upwards as energy is absorbed.
- Examples
- Photosynthesis: Plants absorb sunlight to convert CO₂ and H₂O into glucose and oxygen.
- Thermal decomposition: Heating calcium carbonate (CaCO₃ → CaO + CO₂).
- Dissolving ammonium chloride (NH₄Cl) in water absorbs heat.
- Electrolysis: Uses electrical energy to split compounds like water into H₂ and O₂.
- Applications
- Used in cold packs, photosynthesis for food production, and processes requiring energy storage.