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States of Transformation: Nature of Physical and Chemical Changes

December 18, 2023 588 0

Dynamic Transformation: Chemistry of Physical and Chemical Changes: 

Physical and chemical changes are fundamental concepts in chemistry. Physical changes involve alterations in the state or form of matter without changing its chemical composition. In contrast, chemical changes result in a new substance with distinct properties. Chemical reactions, such as combustion or rusting, exemplify this transformation. 

What is the significance of transformation in pure substances during Physical Changes?

  • Meaning: It refers to changing the state of a pure substance between solid, liquid, or gas phase. 
    • Example: Physical properties change during tempering steel, crystallization, and melting. 

What role does transformation play in Matter through Chemical Changes?

  • Meaning: Any change that brings change in the chemical properties of matter and results in new substances is called chemical change. 
    • Example: Burning a candle etc

Purity: Fixed Structure and types of Pure Substances

  • Meaning: Pure substances are the substances that are made up of only one kind of particle and have a fixed or constant structure.

Chemical Composition and Transformation: Pure Substances Classified into Elements and Compounds

  • On the basis of their chemical composition, substances can be classified either as elements or compounds as follows. 

Chemical Composition and Transformation: Pure Substances Classified into Elements and Compounds

Elemental Transformation: Historical and Modern Divisions of Metals, Non-metals and Metalloids:

  • Historical Evolution of the Term ‘Element’ from Boyle to Lavoisier: Robert Boyle, first to use the term element in 1661, was defined by Antoine Laurent Lavoisier, in the 18th century, as a fundamental form of matter that cannot be further decomposed into simpler substances through chemical reactions.
  • Division: Elements can be normally divided into metals, nonmetals and metalloids.

Properties of Metals: Shining, Conductive, and Resonant Characterstics:

  • They have a lustre (shine).
  • They have a silvery-grey or golden-yellow colour.
  • They conduct heat and electricity.
  • They are ductile (can be drawn into wires).
  • They are malleable (can be hammered into thin sheets).
  • They are sonorous (make a ringing sound when hit).
  • Examples of metals include gold, silver, copper, iron, sodium, potassium etc. Mercury is the only metal that is liquid at room temperature.

Metalloids: These are elements showing properties between those of metals and nonmetals, examples are boron, silicon, germanium.

Properties of Non-Metal: Colors, Conductivity, and Malleability

  • They display a variety of colours.
  • They are poor conductors of heat and electricity.
  • They are not lustrous, sonorous or malleable.
  • Examples of non-metals are hydrogen, oxygen, iodine, carbon (coal, coke), bromine, chlorine etc

 

 Mixtures and Compounds

Mixtures Compounds
Elements or compounds just mix together to form a mixture and no new compound is formed. Elements react to form new compounds.
A mixture has a variable composition. The composition of each new substance is always fixed.
A mixture shows the properties of the constituent substances. The new substance has totally different properties.
The constituents can be separated fairly easily by physical methods. The constituents can be separated only by chemical or electrochemical reactions.

 

Are Compounds Formed through Elemental Transformation?

Meaning: A compound is a substance composed of two or more elements, chemically combined with one another in a fixed proportion.

Schematic classification of matter

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UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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