- Thermal decomposition involves heating a compound to break it into simpler substances, e.g.,
2Pb(NO₃)₂ ⟶ 2PbO + 4NO₂ + O₂ (brown fumes of NO₂ observed). - Electrolytic decomposition uses electricity to decompose compounds, e.g.,
2H₂O ⟶ 2H₂ + O₂ (Electrolysis of water gives hydrogen and oxygen gases). - Photodecomposition occurs when light energy breaks down a compound, e.g.,
2AgCl ⟶ 2Ag + Cl₂ (white silver chloride turns grey in sunlight). - Thermal decomposition of calcium carbonate produces lime (CaO) and CO₂ gas, which turns lime water milky.
- Decomposition reactions are usually endothermic and require heat, light, or electricity to occur (e.g., the decomposition of ferrous sulphate, calcium carbonate, or sugar).
Topics
Gravitation
- Concept of Gravitation
- Force and Motion
- Centripetal Force
- Kepler’s Laws
- Law of Orbit or Kepler's First Law
- Law of Areas or Kepler's Second Law
- Law of Periods or Kepler's Third Law
- Newton's Universal Law of Gravitation
- Uniform Circular Motion (UCM)
- Earth’s Gravitational Force
- Earth’s Gravitational Acceleration
- Mass and Weight
- Gravitational Waves
- Free Fall
- Gravitational Potential Energy
- Escape Velocity
- Weightlessness in Space
Periodic Classification of Elements
- Classification of Elements
- Dobereiner’s Triads
- Newland's Law of Octaves
- Mendeleev’s Periodic Table
- Insights into Mendeleev’s Periodic Table
- Modern Periodic Law
- The Modern Periodic Table
- Structure of the Modern Periodic Table
- Modern Periodic Table and Electronic Configuration of Elements
- Groups and Electronic Configuration
- Periods and Electronic Configuration
- Periodic Trends in the Modern Periodic Table
- Atomic Size
- Metallic and Non-metallic Characters
- Gradation in Halogen Family
Chemical Reactions and Equations
- Chemical Reaction
- Chemical Equations
- Balancing Chemical Equation
- Types of Chemical Reactions > Combination Reaction
- Types of Chemical Reactions > Decomposition Reaction
- Types of Chemical Reactions > Single Displacement Reaction
- Types of Chemical Reactions > Double Displacement Reaction
- Endothermic and Exothermic Processes
- Rate of Chemical Reaction
- Factors Affecting the Rate of a Chemical Reaction
- Chemical Properties of Carbon Compounds > Oxidation
- Chemical Properties of Carbon Compounds > Reduction
- Corrosion of Metals
- Rancidity
Effects of Electric Current
- Electric Circuit
- Heating Effect of Electric Current
- Introduction to Magnetic Effect of Current
- Right-hand Thumb Rule
- Applications of Biot-Savart's Law > Magnetic Field at the Axis of a Circular Current-carrying Loop
- Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
- Force on a Current-Carrying Conductor Placed in a Uniform Magnetic Field
- Fleming’s Left Hand Rule
- Electric Motor
- Electromagnetic Induction
- Galvanometer
- Faraday's Laws of Electromagnetic Induction
- Fleming’s Right Hand Rule
- Alternating current (AC) and Direct Current (DC)
- Electric Generator
Heat
Refraction of Light
Lenses
- Concept of Lenses
- Images Formed by Convex Lenses
- Images Formed by Concave Lenses
- Sign Convention
- Lens Formula
- Magnification
- Power of a Lens
- Combination of Lenses
- Defects of Vision and Their Corrections > Myopia
- Defects of Vision and Their Corrections > Hypermetropia
- Defects of Vision and Their Corrections > Presbyopia
- Apparent Size of an Object
- Use of Concave Lenses
- Use of Convex Lenses
- Persistence of Vision
Metallurgy
- Physical Properties of Metals
- Physical Properties of Non-metal
- Chemical Properties of Metal
- Reactions of Metals
- Reactivity Series of Metals
- Chemical Properties of Non-metal
- Ionic Compounds
- Metallurgy
- Basic Principles of Metallurgy > Concentration of Ores
- Basic Principles of Metallurgy > Extraction of Metals
- Basic Principles of Metallurgy > Refining of Metals
- Corrosion of Metals
- Prevention of Corrosion
Carbon Compounds
- Bonds in Carbon Compounds
- Carbon: A Versatile Element
- Hydrocarbons
- Straight chains, Branched chains, and Rings of Carbon atoms
- Functional Groups in Carbon Compounds
- Homologous Series
- Nomenclature
- Chemical Properties of Carbon Compounds > Combustion
- Chemical Properties of Carbon Compounds > Oxidation
- Chemical Properties of Carbon Compounds > Addition Reaction
- Chemical Properties of Carbon Compounds > Substitution Reaction
- Ethanol
- Ethanoic Acid
- Macromolecules and Polymers
Space Missions
School of Elements
The Magic of Chemical Reactions
- Chemical Equations
- Types of Chemical Reactions > Combination Reaction
- Types of Chemical Reactions > Decomposition Reaction
- Types of Chemical Reactions > Single Displacement Reaction
- Types of Chemical Reactions > Double Displacement Reaction
- Chemical Properties of Carbon Compounds > Oxidation
- Types of Double Displacement: Neutralization Reaction
The Acid Base Chemistry
- Properties of Acids > Physical Properties
- The pH Scale
- Acids, Bases and Their Reactivity
- Acid or a Base in a Water Solution
- Preparation and Uses of Baking Soda
- Preparation and Uses of Bleaching Powder
- Preparation and Uses of Washing Soda
- Preparation and Uses of Plaster of Paris
- Chemicals from Common Salt - Soap as a Salt
The Electric Spark
All about Electromagnetism
- Magnetic force
- Bar Magnet and Solenoid Analogy
- Right-hand Thumb Rule
- Applications of Biot-Savart's Law > Magnetic Field at the Axis of a Circular Current-carrying Loop
- Applications of Ampere’s Circuital Law > Magnetic Field of a Long Straight Solenoid
- Force on a Current-Carrying Conductor Placed in a Uniform Magnetic Field
- Electric Motor
- Electromagnetic Induction
- A.C. Generator
- Simple D.C. Motor
- Household Electrical Circuits
Wonders of Light 1
Wonders of Light 2
Striving for better Environment 1
- Abatement of Pollution
- Sustainable Use of Resources
- Definition: Decomposition Reaction
- Definition: Thermal Decomposition
- Key Points: Decomposition Reaction
CBSE: Class 10
Maharashtra State Board: Class 10
Maharashtra State Board: Class 10
Definition: Decomposition Reaction
A single reactant breaks down to give simpler products. This is a decomposition reaction.
OR
The chemical reaction in which two or more products are formed from a single reactant is a decomposition reaction.
CBSE: Class 10
Definition: Thermal Decomposition
When a decomposition reaction is carried out by heating, it is called thermal decomposition.
CBSE: Class 10
Maharashtra State Board: Class 10
Maharashtra State Board: Class 10
Key Points: Decomposition Reaction
Maharashtra State Board: Class 10
Experiment
1. Aim: To observe and understand decomposition reactions, where a single reactant breaks down into two or more simpler substances.
2. Requirements
- Apparatus: evaporating dish, test tubes, bent tube, rubber cork, Bunsen burner.
- Chemicals: sugar, calcium carbonate (CaCO₃), sulphuric acid, freshly prepared lime water.
4. Procedure
Experiment 1: Decomposition of Sugar
- Take some sugar in an evaporating dish.
- Heat it using a Bunsen burner and observe the changes.
- A black residue (carbon) forms, and water (H₂O) vapour is released.
\[\mathrm{C}_{12}\mathrm{H}_{22}\mathrm{O}_{11}\xrightarrow{\mathrm{Heat}}12C+11H_2O\]
Experiment 2: Decomposition of Calcium Carbonate
- Take some calcium carbonate (CaCO₃) in a test tube.
- Fit a bent tube into the test tube using a rubber cork.
- Insert the other end of the bent tube into another test tube containing freshly prepared lime water.
- Heat the calcium carbonate strongly. The lime water turns milky, indicating the presence of carbon dioxide (CO₂) gas.
\[\mathrm{CaCO}_3(s)\xrightarrow{\Delta}\mathrm{CaO}(s)+\mathrm{CO}_2\uparrow\]
Decomposition of calcium carbonate
Experiment 3: Electrolysis of Water
- Pass electric current through acidulated water.
- Observe the formation of hydrogen (H₂) and oxygen (O₂) gases.
\[2H_2O(l)\xrightarrow{\text{Electrical Energy}}2H_2\uparrow+O_2\uparrow\]
5. Conclusion: A decomposition reaction occurs when a single reactant breaks down into two or more simpler substances. These reactions can be thermal (heat-driven), electrolytic (electricity-driven), or biological (natural degradation by microorganisms). Decomposition reactions are crucial in nature, industry, and energy production, such as in the formation of biogas from organic waste.
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