Matter in Our Surroundings: Complete Study Note

Welcome to your comprehensive guide on Matter. Whether you are preparing for school exams or competitive tests, this breakdown covers everything from the basics to high-yield exam questions.

1. The Fundamental Definition of Matter

Definition: Anything that occupies space (Volume) and has mass.

Examples: Air, food, stones, clouds, stars, plants, water, sand.

Abstract concepts like love, hate, thought, cold, or smell (the sensation) are NOT matter.
However, "smell of perfume" IS matter because it refers to the physical volatile particles of the perfume diffusing in the air.

Classifications:

Ancient (Indian): "Panch Tatva" (Air, Earth, Fire, Sky, Water).
Modern: Based on Physical properties (States) and Chemical nature (Elements/Compounds).

2. Physical Nature of Matter (Particulate Nature)

Matter is not continuous like a wooden block; it is made of tiny particles (like sand).

A. Characteristics of Particles

They are extremely small: A tiny crystal of Potassium Permanganate ($KMnO_4$) can color 1000L of water. (Proof that matter is divisible into tiny atoms/molecules).
They have space between them: When salt dissolves in water, the water level does not rise because salt particles hide in the intermolecular spaces.
They are continuously moving: They possess Kinetic Energy.
Brownian Motion: This is the scientific term for the random, zigzag motion of particles. Remember this for exams!
They attract each other: The force that keeps matter together (Solids > Liquids > Gases).

Diffusion: The intermixing of particles of two different types of matter on their own.
Rule: Rate of diffusion increases with Temperature (Heat → Higher Kinetic Energy → Faster movement).

3. States of Matter (The Big Three)

Feature	Solid	Liquid	Gas
Shape	Definite	Indefinite (Takes container shape)	Indefinite
Volume	Definite	Definite	Indefinite
Compressibility	Negligible	Low	High (e.g., LPG, CNG)
Particle Motion	Vibrate at fixed positions	Slide over each other	Random, high speed

Important Exam Question (Density Anomaly):
Generally, solids are denser than liquids. Why does Ice float on water?
Answer: Ice has a cage-like structure that creates vacant spaces, making its volume larger and density lower than liquid water.

4. The Two "New" States of Matter (High-Yield Topic)

Modern science recognizes 5 states. Competitive exams love these additions.

4th State: Plasma

What is it? Super energetic, ionized gas (charged particles).
Where? Sun and Stars (due to high temperature), Neon signs.

5th State: Bose-Einstein Condensate (BEC)

Origin: Predicted by Indian physicist Satyendra Nath Bose and Albert Einstein (1920).
Creation: Formed by cooling a gas of extremely low density to super low temperatures (near Absolute Zero).

Always remember the name S.N. Bose. Examiners frequently ask about the contribution of Indian scientists in this discovery.

5. Change of State (Phase Transitions)

A. Effect of Temperature

Melting Point: Solid → Liquid. (Ice melts at $273.15 K$ or $0^\circ C$).
Boiling Point: Liquid → Gas. (Water boils at $373 K$ or $100^\circ C$).
Sublimation: Solid ↔ Gas (Directly).

Examples to Memorize for Sublimation: Camphor (Kapur), Ammonium Chloride ($NH_4Cl$), Naphthalene balls, Iodine, Anthracene.

B. Latent Heat (The "Hidden" Energy)

Why does temperature stay constant during melting/boiling? Because the heat supplied is used to break the forces of attraction, not to raise the temperature.

Q: Why does steam cause more severe burns than boiling water at $100^\circ C$?
A: Steam possesses extra energy in the form of Latent Heat of Vaporization.

6. Evaporation vs. Boiling

Don't confuse them! Boiling is a bulk phenomenon (happens to the whole liquid), while Evaporation is a surface phenomenon.

Why does Evaporation cause cooling?
Particles absorb energy from the surroundings to change state, leaving the area cool.
Examples: Water in an Earthen Pot (Matka), Acetone on your palm, Cotton clothes in summer.

7. Important Units and Conversions

In Science, units are everything.

SI Unit of Temperature: Kelvin (K).
Formula: $K = ^\circ C + 273$
- $0^\circ C = 273 K$
- $100^\circ C = 373 K$
Absolute Zero: 0 Kelvin (The theoretical lowest possible temperature).
Pressure: Pascal (Pa). (1 atm = $1.01 \times 10^5$ Pa).

8. Summary of Exam-Ready Questions

Q: Which state of matter consists of super-excited ionized gases?
A: Plasma.
Q: Naphthalene balls disappear after some time. This phenomenon is called?
A: Sublimation.
Q: What is the chemical name of Dry Ice?
A: Solid Carbon Dioxide ($CO_2$).
Q: Who predicted the 5th state of matter?
A: S.N. Bose and Albert Einstein.

Study Tip: Read this breakdown twice. First for flow, second to memorize the specific examples of Sublimation and the unit conversions!