ᒪEᗩᖇᑎIᑎG ᒍᑌᑎᑕTIOᑎ
CBSE
CLASS 10 SCIENCE
CHAPTER 1 CHEMICAL REACTION AND EQUATIONS
NOTES
1. Chemical Equation:
👉A chemical equation is a symbolic representation of a chemical reaction.
👉It consists of reactants on the left-hand side (LHS) and products on the right-hand side (RHS), separated by an arrow.
👉For example: 2H₂ + O₂ → 2H₂O
2. Balanced Chemical Equations:
👉In a balanced chemical equation, the number of atoms of each element is equal on both sides of the equation.
👉Balancing involves adjusting the coefficients in front of the reactants and products.
👉The law of conservation of mass is followed during balancing.
3. Types of Chemical Reactions:
a. Combination Reaction:
👉Two or more substances combine to form a new compound.
👉Example: A + B → AB
b.Decomposition Reaction:
👉A compound breaks down into two or simpler substances.
👉Example: AB → A + B
c. Displacement Reaction:
👉An element displaces another element from its compound.
👉Example: A + BC → AC + B
d. Double Displacement Reaction:
👉Exchange of ions takes place between two compounds.
👉Example: AB + CD → AD + CB
e.Redox Reaction:
👉Combination of reduction and oxidation reactions.
👉In a reduction reaction, a substance gains electrons, while in an oxidation reaction, a substance loses electrons.
4. Oxidation and Reduction:
👉Oxidation: The addition of oxygen, loss of hydrogen, or loss of electrons.
👉Reduction: The addition of hydrogen, loss of oxygen, or gain of electrons.
👉Reducing agent: Substance that causes reduction by losing electrons.
👉Oxidizing agent: Substance that causes oxidation by gaining electrons.
5. Effects of Oxidation Reactions:
👉Combustion: Rapid oxidation accompanied by the release of energy in the form of heat and light.
👉Corrosion: The gradual destruction of metals by oxidation in the presence of moisture, air, or other substances.
6. Importance of Chemical Reactions:
👉Respiration: The process of breaking down food molecules to release energy.
👉Photosynthesis: The process by which green plants prepare their own food using sunlight, water, and carbon dioxide.
👉Rusting: The formation of iron oxide (rust) due to the reaction of iron with oxygen in the presence of moisture.
⭐Remember to refer to your textbook and class notes for a more comprehensive understanding of the chapter.
