Key Topics Covered:

1. What is a Chemical Reaction?

   • Definition: A chemical reaction is the process where reactants undergo a transformation to form new substances (products) with different properties.
   • Reactants and Products: Introduction to the idea that substances change in nature during a chemical reaction.

2. Evidence of Chemical Reactions

   • Physical changes like color change, temperature change, gas evolution, and precipitate formation as indicators of a chemical reaction.
   • Examples: The reaction of zinc with hydrochloric acid (gas evolution) or heating copper sulfate to form copper oxide.

3. Overview of Types of Chemical Reactions

   • Briefly introduce the different types of reactions that will be covered in detail in subsequent parts.