Here's a breakdown:
* Formation of bonds: When atoms come together to form molecules, they share or transfer electrons, creating new bonds. This releases energy, making the reaction exothermic.
* Breaking of bonds: To break existing bonds within molecules, energy needs to be supplied. This makes the reaction endothermic.
The process of bond breaking and forming results in the formation of new substances with different properties than the original reactants.
Examples:
* Combustion: Bonds in fuel molecules like methane (CH4) are broken, and new bonds are formed with oxygen (O2) to create carbon dioxide (CO2) and water (H2O).
* Photosynthesis: Sunlight provides energy to break the bonds in carbon dioxide and water molecules, forming new bonds in glucose (sugar) and oxygen.
Let me know if you'd like more examples or explanation on a specific chemical reaction!
