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2. Chemical Changes and Reactions

Chemical changes are defined by the formation of new substances and are accompanied by identifiable reactions, such as temperature changes and gas evolution. Various types of chemical reactions include combination, decomposition, displacement, double displacement, neutralization, and combustion, each characterized by unique properties. Energy changes during reactions can be exothermic or endothermic, and the law of conservation of mass holds true, indicating that mass is neither created nor destroyed in these processes.

Sections

  • 2

    Chemical Changes And Reactions

    Chemical changes lead to new substances and are characterized by various observable properties.

    Learning Practice

  • 2.1

    Introduction

    A chemical change leads to the formation of new substances, accompanied by a chemical reaction.

    Learning Practice

  • 2.2

    Characteristics Of Chemical Changes

    Chemical changes result in new substances with distinct properties and are characterized by several signs.

    Learning Practice

  • 2.3

    Types Of Chemical Reactions

    This section outlines the various types of chemical reactions, explaining how different substances interact to form new products.

    Learning Practice

  • 2.3.1

    Combination Reaction

    A combination reaction occurs when two or more substances combine to form a single product.

    Learning Practice

  • 2.3.2

    Decomposition Reaction

    Decomposition reactions occur when a compound breaks down into simpler substances, often under heat, electricity, or light.

    Learning Practice

  • 2.3.3

    Displacement Reaction

    Displacement reactions involve a more reactive element replacing a less reactive element from a compound.

    Learning Practice

  • 2.3.4

    Double Displacement Reaction

    Double displacement reactions involve the exchange of ions between two compounds resulting in the formation of new products.

    Learning Practice

  • 2.3.5

    Neutralization Reaction

    Neutralization reactions occur when acids react with bases to form salt and water, playing a vital role in chemistry.

    Learning Practice

  • 2.3.6

    Combustion Reaction

    A combustion reaction occurs when a substance reacts with oxygen, producing heat and light.

    Learning Practice

  • 2.4

    Energy Changes In Chemical Reactions

    This section explains energy changes in chemical reactions, focusing on exothermic and endothermic reactions.

    Learning Practice

  • 2.4.1

    Exothermic Reactions

    Exothermic reactions are chemical processes that release heat, increasing the temperature of the surroundings.

    Learning Practice

  • 2.4.2

    Endothermic Reactions

    Endothermic reactions are chemical reactions that absorb heat, resulting in a decrease in the temperature of the surroundings.

    Learning Practice

  • 2.5

    Conditions For Chemical Reactions

    This section outlines the essential conditions necessary for chemical reactions to occur.

    Learning Practice

  • 2.6

    Representation Of Chemical Reactions

    This section discusses how chemical reactions can be represented using word equations and chemical equations.

    Learning Practice

  • 2.7

    Law Of Conservation Of Mass

    The Law of Conservation of Mass states that mass is neither created nor destroyed during a chemical reaction.

    Learning Practice

References

ch2.pdf

Class Notes

Memorization

What we have learnt

  • Chemical changes lead to th...
  • Different types of chemical...
  • Energy changes during react...

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