Chemical Reactions and Equations Class 10 Science — Revision Notes
This chapter covers the representation of chemical reactions through equations and classification of different types of reactions based on their characteri
TL;DR: This chapter covers the representation of chemical reactions through equations and classification of different types of reactions based on their chara…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
This chapter covers the representation of chemical reactions through equations and classification of different types of reactions based on their characteri
Chemical Equation and Balancing
- A chemical equation represents a chemical reaction using symbols and formulas
- Balanced equation has equal number of atoms of each element on both sides
- Unbalanced equation is called skeletal equation
- Law of conservation of mass: matter is neither created nor destroyed
Types of Chemical Reactions
- Combination reaction: A + B = AB (e.g., C + O2 = CO2)
- Decomposition reaction: AB = A + B (e.g., 2H2O = 2H2 + O2)
- Displacement reaction: A + BC = AC + B (more reactive element displaces less reactive)
- Double displacement reaction: AB + CD = AD + CB
Oxidation and Reduction
- Oxidation is loss of electrons or gain of oxygen
- Reduction is gain of electrons or loss of oxygen
- Redox reaction involves both oxidation and reduction simultaneously
- Oxidizing agent causes oxidation, reducing agent causes reduction
Effects of Oxidation Reactions
- Corrosion: deterioration of metals like rusting of iron
- Rancidity: oxidation of fats and oils causing unpleasant smell and taste
- Prevention through painting, oiling, coating with grease
Key Terms
- Chemical Equation: Symbolic representation of a chemical reaction showing reactants and products
- Catalyst: A substance that speeds up a reaction without being consumed
- Precipitate: An insoluble solid formed when two solutions react
Frequently Asked Questions
What is the difference between physical and chemical change?
Physical change is reversible and involves change in state or appearance without forming new substances. Chemical change is irreversible, forms new substances with different properties.
How do you balance a chemical equation?
Count atoms of each element on both sides. Use coefficients to make atoms equal on both sides. Never change subscripts in chemical formulas.
More Class 10 Science Revision Notes
- Acids Bases and Salts
- Metals and Non-metals
- Carbon and its Compounds
- Life Processes
- Control and Coordination
- How do Organisms Reproduce
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