1. Reactants: The starting materials in a chemical reaction are called reactants. They are the substances that will be transformed.
2. Bonds Break: Energy is required to break the chemical bonds holding the atoms together in the reactants. This energy can come from heat, light, or other forms of energy.
3. Bonds Form: As the old bonds break, new bonds form between the atoms, creating new molecules. This process releases energy, which can be in the form of heat, light, or other forms of energy.
4. Products: The new substances formed in a chemical reaction are called products. They have a different chemical composition and often different properties than the reactants.
Key Concepts:
* Conservation of Mass: The total mass of the reactants before a chemical reaction equals the total mass of the products after the reaction. Atoms are not created or destroyed, they are simply rearranged.
* Energy Changes: Chemical reactions involve either the release (exothermic) or absorption (endothermic) of energy.
* Rates of Reaction: The speed at which a reaction occurs can be influenced by factors like temperature, concentration, and the presence of catalysts.
Example:
The reaction between hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) is a classic example:
* Reactants: Hydrogen (H2) and Oxygen (O2)
* Bonds Break: The bonds in hydrogen and oxygen molecules break.
* Bonds Form: New bonds form between hydrogen and oxygen atoms, creating water molecules (H2O).
* Products: Water (H2O)
In a nutshell: Chemical reactions are all about rearranging atoms and molecules to create new substances with different properties. This process involves breaking old bonds, forming new bonds, and releasing or absorbing energy.
