States of Matter and Phase Changes

Definition: The branch of science dealing with the composition, properties, structure of matter, changes in matter, and the laws governing these changes.

States of Matter: Earth (Solids), Air (Gases), Sea (Liquids), and Sky (Plasma).

• Physical Chemistry: Study of physical properties and behavior of matter at atomic/molecular level, and laws governing changes.
• Organic Chemistry: Study of covalent compounds of Carbon (Hydrocarbons) and their derivatives (except simple salts like carbonates). Essential for life.
• Inorganic Chemistry: Study of synthesis and properties of compounds not containing C-H bonds. Used in metals, medicines, glass, etc.
• Biochemistry: Study of chemical substances and processes in living organisms (enzymes, DNA).
• Analytical Chemistry: Analysis of separation, identification, and quantification of matter components.
• Nuclear Chemistry: Study of reactions in the nucleus (radioactivity, nuclear processes).
• Environmental Chemistry: Study of chemical phenomena in the environment and effects of pollution.
• Polymer Chemistry: Study of structure and synthesis of polymers (macromolecules) like plastics and proteins.

Matter: Anything that has mass and occupies space.

States: Solid, Liquid, Gas, Plasma.

Definition: Simplest form of matter made of same kind of atoms with same atomic number. Cannot be broken down by ordinary chemical means.

Types: Metals (e.g., Iron, Gold), Non-metals (e.g., Oxygen, Nitrogen), Metalloids, Noble Gases.

State: Mostly solid, few liquid (Mercury, Bromine), few gas (Oxygen, Chlorine).

Compound: Pure substance of two or more elements chemically combined in a fixed ratio by mass. Loses individual element properties (e.g., Water, CO2).

Mixture: Two or more substances physically mixed without fixed ratio. Retains individual properties. Can be separated physically.

• Homogeneous: Uniform composition (e.g., Salt solution, Air).
• Heterogeneous: Non-uniform composition (e.g., Soil, Rock).

• Gases: Particles widely apart, random motion, negligible attraction, highly compressible, low density.
• Liquids: Particles closer than gases, strong attraction, fixed volume but shape of container, difficult to compress, higher density than gases.
• Solids: Particles closely packed, strong attraction, fixed shape and volume, vibrate at fixed positions, incompressible, high density.

Plasma: Fourth state of matter. Ionized gaseous mixture of electrons, ions, and neutral atoms (e.g., Sun, Lightning, Fluorescent lights).

Supercritical Fluid: State at high T and P showing properties of both gas (penetration) and liquid (dissolving power). Used in extraction.

Liquid Crystal: State between liquid and solid crystal. Turbid liquid that flows but has ordered structure. Used in LCDs.

Definition: Existence of an element in more than one form in the same physical state.

• Oxygen: O2 (Oxygen gas), O3 (Ozone).
• Sulphur: Rhombic (stable below 96°C) and Monoclinic (stable above 96°C).
• Carbon:
  • Diamond: Hardest, tetrahedral crystalline structure, non-conductor, brilliant (total internal reflection).
  • Graphite: Soft, hexagonal layered structure, conductive, slippery (lubricant).
  • Buckyball (C60): Football-shaped fullerene, stable at high T.
  • Graphene: Single 2D layer of carbon, hexagonal, strongest material, high conductivity (Miracle Material).

• Solution: Homogeneous mixture of solute (lesser amount) and solvent (larger amount). E.g., Salt water.
• True Solution: Solute completely dissolved, invisible to naked eye, passes through filter paper.
• Colloid: Intermediate mixture (e.g., Milk, Starch). Particles bigger than true solution but don't settle. Scatter light (Tyndall effect). Pass through filter.
• Suspension: Heterogeneous mixture (e.g., Chalk in water). Particles visible, settle on standing, do not pass through filter.

Definition: Amount of solute dissolved in 100g solvent at a particular temperature to form a saturated solution.

Types of Solutions:

• Saturated: Contains maximum solute at given Temp. Cannot dissolve more.
• Unsaturated: Can dissolve more solute.
• Supersaturated: Contains more solute than saturated solution (unstable).

Effect of Temperature:

• Increases: For most salts (KNO3, KCl).
• Decreases: For gases (CO2 in soda) and some salts (Li2CO3, CaCrO4).
• No Change: NaCl solubility barely changes with Temp.