Changes in states of matter

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Changes in states of matter

1. What is Matter ?

       i.  Matter is anything that has mass and occupies space.

     ii.   Everything around us — like water, air, wood, and iron — is made of matter.

    iii.   Matter exists in four main states:

o    Solid

o    Liquid

o    Gas

o    Plasma

2. States of Matter

(a) Solid

       i.  Solids have a fixed shape and a fixed volume.

      ii.   The particles in solids are tightly packed.

     iii.    Solids cannot be easily compressed.

      iv.    Example: Ice, Iron, Wood.

(b) Liquid

       i.   Liquids have a fixed volume but no fixed shape.

      ii.   They take the shape of the container.

     iii.   Liquids can flow and are slightly compressible.

     iv.   Example: Water, Milk, Oil.

(c) Gas

       i.  Gases have neither a fixed shape nor a fixed volume.

      ii.   They can be easily compressed.

     iii.    The particles in gases move freely and are far apart.

     iv.     Example: Air, Oxygen, Carbon dioxide.

(d) Plasma

       i.   Plasma is the fourth state of matter.

      ii.   It contains free electrons and ions.

     iii.    It conducts electricity and glows when charged.

     iv.    Example: Sun, Lightning, Tubelight, Stars.

3. Changes in States of Matter

Matter can change from one state to another when it is heated or cooled.

(a) Melting (Solid → Liquid)

       i.  When a solid is heated, it changes into a liquid.

      ii.   This process is called melting or fusion.

     iii.    Example: Ice melts to form water.

(b) Freezing (Liquid → Solid)

       i.   When a liquid is cooled, it changes into a solid.

      ii.   This process is called freezing or solidification.

     iii.    Example: Water freezes to form ice.

(c) Vaporization (Liquid → Gas)

       i.   When a liquid is heated, it changes into a gas.

      ii.   This process is called vaporization or boiling.

     iii.   Example: Water boils to form steam.

(d) Condensation (Gas → Liquid)

       i.  When a gas is cooled, it changes into a liquid.

      ii.   This process is called condensation.

      iii.   Example: Steam cools to form water droplets.

(e) Sublimation (Solid → Gas)

       i.  Some solids change directly into gas without becoming liquid.

      ii.   This process is called sublimation.

      iii.     Example: Camphor and naphthalene turn into vapor directly.

(f) Deposition (Gas → Solid)

       i.  When a gas changes directly into a solid without becoming a liquid.

      ii.   This process is called deposition.

     iii.   Example: Frost formation on cold glass.

(g) Ionization (Gas → Plasma)

       i.  When a gas is heated to a very high temperature, its atoms lose electrons.

      ii.   The gas becomes a collection of charged particles (ions and electrons).

     iii.   This state is called plasma.

     iv.    Example: The Sun, stars, lightning, and tubelights contain plasma.

(h) Deionization (Plasma → Gas)

       i.  When plasma cools down, the ions recombine to form neutral atoms.

      ii.   It changes back into a gas.

     iii.   This process is called deionization.

4. Important Points to Remember

       i.  Heat energy causes matter to change its state.

      ii.  Increasing temperature changes solid → liquid → gas → plasma.

     iii.  Decreasing temperature changes plasma → gas → liquid → solid.

     iv.  These are physical changes because no new substance is formed.

      v.  Plasma is the most common state of matter in the universe (found in stars and the Sun).