By the end of this lesson, you’ll be able to:

• Define chemical reactions and understand their significance:
  • A chemical reaction is a process where atoms are rearranged to form new substances
  • Learn how reactions are central to biology, industry, energy, and environmental systems
  • Recognize signs of chemical change: color change, gas production, temperature shift, precipitate formation
• Identify the roles of reactants and products:
  • Reactants are the starting substances that undergo change
  • Products are the new substances formed after the reaction
  • Example: In the reaction 2H₂ + O₂ → 2H₂O, hydrogen and oxygen are reactants, water is the product
• Interpret and balance chemical equations:
  • Chemical equations represent reactions using chemical formulas and symbols
  • Learn to balance equations to obey the Law of Conservation of Mass
  • Practice identifying coefficients and subscripts to ensure equal atoms on both sides
• Explore various types of chemical reactions:
  • Synthesis – two or more substances combine to form one product (e.g., A + B → AB)
  • Decomposition – one substance breaks down into simpler parts (e.g., AB → A + B)
  • Single Replacement – one element replaces another in a compound (e.g., A + BC → AC + B)
  • Double Replacement – two compounds exchange components (e.g., AB + CD → AD + CB)
  • Combustion – a substance reacts with oxygen, releasing energy (e.g., hydrocarbons + O₂ → CO₂ + H₂O