1. Rearrangement of Atoms:
* The atoms of the original substances break their existing bonds and form new bonds with each other.
* This rearrangement creates a different arrangement of atoms within the compound.
2. Formation of New Bonds:
* Chemical bonds are forces that hold atoms together.
* In a chemical reaction, new bonds are formed between the atoms of the reacting substances.
3. Change in Properties:
* The resulting compound has different physical and chemical properties compared to the original substances.
* For example, water (H₂O) is formed from the chemical combination of hydrogen and oxygen, which are both gases. Water, however, is a liquid with very different properties.
4. Energy Changes:
* Chemical reactions can release energy (exothermic reactions) or absorb energy (endothermic reactions).
* This energy change can be observed as heat, light, or other forms of energy.
Example:
Imagine you mix baking soda (sodium bicarbonate) and vinegar (acetic acid). They react to form carbon dioxide gas, water, and sodium acetate.
* Original substances: Baking soda (NaHCO₃) and vinegar (CH₃COOH)
* New substance: Carbon dioxide (CO₂), water (H₂O), and sodium acetate (CH₃COONa)
The resulting mixture has a different appearance, smell, and chemical properties than the original baking soda and vinegar.
In short, when substances chemically combine, they create a new substance with different properties by rearranging atoms and forming new chemical bonds.
