Ch 01: Matter & States of Matter

🧪 Matter — At a Glance

📘 Definition

Anything that has mass and occupies space. Made up of molecules and atoms. e.g., Water, Air, Iron.

States of Matter

22.4 L

1 Mole Gas at STP

18.02 amu

Molecular Mass of H₂O

100°C

Boiling Point of Water

Properties: Interstitial space · Constant particle motion · Intermolecular attraction
Physical classification: Solid · Liquid · Gas · Plasma · BEC
Chemical classification: Pure substance (Element/Compound) · Mixture (Homogeneous/Heterogeneous)
Key laws: Boyle's (1622) · Charles's (1787) · Gay-Lussac's (1809) · Dalton's

📊 Elemental Composition — Earth's Crust & Atmosphere

EARTH'S CRUST

O₂ 46.8%

Si 27.7%

Al 8%

Fe 5%

Others

ATMOSPHERE

N₂ 78%

O₂ 21%

CO₂ 0.03%+

⚠️ Exam Trap — Earth's Crust

Most abundant element in Earth's crust = Oxygen (O₂) — 46.8%
Second most abundant = Silicon (Si) — 27.7%
Most abundant gas in atmosphere = Nitrogen (N₂) — 78%
CO₂ in atmosphere = 0.03% (only)

🧊 Five States of Matter

🧊

Solid

Definite shape & volume | Strong IMF | Negligible compressibility

💧

Liquid

No definite shape | Definite volume | Higher compressibility than solid

💨

Gas

No definite shape/volume | Weak IMF | High compressibility

⚡

Plasma

Ionised gas | Excited particles | 4th state | Found in Sun & stars

❄️

BEC

Bose-Einstein Condensate | 5th state | Near absolute zero (0 K)

📘 Bose-Einstein Condensate (BEC)

Discovery: Satyendra Nath Bose and Albert Einstein (1924)
Formed by dilute gas of Bosons at absolute zero (0 K = −273°C)
Eric Cornell (2001) experimentally created BEC using Rubidium-85 → Nobel Prize in Physics

⚠️ Exam Trap — States

Plasma = 4th state; BEC = 5th state
BEC discovery = Bose & Einstein (1924); Nobel = Eric Cornell (2001)
Gas → Plasma by increasing temperature or ionisation

🌡️ Effect of Temperature on States

Phase Change	Process Name	Example
Solid → Liquid	Melting (Fusion)	Ice → Water
Liquid → Solid	Freezing	Water → Ice
Liquid → Gas	Vaporisation	Water → Steam
Gas → Liquid	Condensation	Steam → Water; Dew, Fog, Mist
Solid → Gas	Sublimation	Camphor, Dry Ice (CO₂), Naphthalene
Gas → Solid	Deposition	Frost formation

Evaporation Rate Increases when

Surface area ↑
Wind speed ↑
Temperature ↑
Humidity ↓

Boiling Point Changes

BP of water = 100°C at sea level
At altitude (pressure ↓) → BP ↓
Sea water BP > normal water (dissolved salts)
Pressure cooker: pressure ↑ → BP ↑

🔩 Types of Solids

Crystalline Solid

Regular ordered structure

Definite geometrical shape
Sharp melting point
Anisotropic — properties differ in different directions
Example: Quartz, NaCl, Ice

Amorphous Solid

Random / disordered structure

Indefinite shape
Range of melting points (not sharp)
Isotropic — properties same in all directions
Example: Glass, Plastic, Rubber

⚠️ Exam Trap — Crystalline vs Amorphous

Crystalline = Anisotropic; Amorphous = Isotropic
Sharp melting point → Crystalline; Range → Amorphous
Glass = amorphous solid (NOT crystalline, even though transparent)
Quartz = crystalline form of SiO₂ (Glass is amorphous SiO₂)

💎 Types of Crystalline Solids

TypeCrystalline Solid	Example	Bonding	Characteristics
Ionic	NaCl	Electron transfer between ions	High MP, brittle, conducts in molten state
Molecular	H₂O (ice)	Weak intermolecular forces	Low MP, soft, poor conductors
Covalent	Diamond	Covalent bonds between atoms	Very hard, very high MP, non-conductor
Metallic	Ag, Fe	Sea of free electrons	Good conductor, ductile, malleable, lustrous

⚠️ Exam Trap — Crystalline Types

Diamond = Covalent solid (hardest natural substance)
NaCl = Ionic solid (NOT covalent)
Metallic solids → "sea of free electrons" → excellent conductors
Molecular solids have lowest melting points (weak forces)

🗂️ Chemical Classification of Matter

Element

One type of atom/molecule

Made of only one kind of particle
Cannot be broken into simpler substances
Types: Metallic & Non-Metallic
Examples: Fe, Cu, Au, O₂, H₂

Compound

Two or more elements in fixed ratio

Elements combined in definite proportions
Can be broken down by chemical/electrolysis
Types: Organic & Inorganic
Examples: H₂O, NaCl, CaCO₃

2H₂ + O₂ → 2H₂OH:O = 1:8 by mass

Pure Substance

Fixed composition, characteristic properties

Properties same regardless of source
Examples: Salt, Sugar, Water
Includes both Elements and Compounds

📘 Mass-Related Terms

1 amu = 1.66056 × 10⁻²⁴ g
Molecular mass of H₂O = 2(1.008) + 16 = 18.02 amu
Equivalent weight = Molecular weight / Valency
Mass% = (Mass of solute × 100) / Total mass of solution

⚗️ Mole Concept

📘 Definition

Amount of substance whose weight equals its formula weight in grams, OR whose volume at STP = 22.4 L (for gas).

No. of Moles = Mass(g) / Molecular (or Atomic) WeightMole Concept Formula

1 Mole Gas at STP

22.4 L

1 Mole contains

6.022×10²³ particles

Avogadro Number

6.022×10²³

🌊 Mixtures

📘 Definition

Combination of two or more substances with variable composition. Components retain their individual properties.

Homogeneous Mixture

Uniform composition throughout

Particle size < 1 nm
No scattering of light
Cannot be separated by filtration
Examples: Sugar in water, Salt in water, Air

Heterogeneous Mixture

Non-uniform composition

Particle size > 10 nm
Shows Tyndall Effect (scattering of light)
Can be separated by filtration/settling
Examples: Oil in water, Soil in water, Chalk in water

⚠️ Exam Trap — Tyndall Effect

Tyndall Effect = scattering of light by particles in a colloid
Seen in heterogeneous mixtures (particle size > 10 nm)
Examples: Milk, Fog, Smoke, Colloidal solutions — all show Tyndall Effect
True solutions (homogeneous) do NOT show Tyndall Effect

⚗️ Methods of Separation of Mixtures

① Evaporation

Salt from water · Dye from ink

② Centrifugation

Butter from milk · Cream from milk

③ Separating Funnel

Oil from water (immiscible liquids)

④ Sublimation

Camphor from compounds · Naphthalene

⑤ Chromatography

Drugs from blood · Pigments from colours

⑥ Distillation

Homogeneous mixture of two liquids

⑦ Crystallisation

Salt from sea water · Purifying sugar

⑧ Decantation

Insoluble particles from liquid (e.g., sand from water)

⚠️ Exam Trap — Separation Methods

Butter from milk → Centrifugation (NOT filtration)
Salt from sea water → Crystallisation (NOT distillation)
Oil from water → Separating funnel (immiscible liquids)
Chromatography → Drugs from blood, pigment separation (smallest scale)
Sublimation → Only for substances that sublime (Camphor, Iodine, Naphthalene)

🔥 Physical vs Chemical Changes

Physical Change

Reversible — No new substance formed

Change in size, shape, state only
Reversible
No new substance formed
Examples: Melting of ice · Breaking pencil · Tearing paper · Boiling water

Chemical Change

Irreversible — New substance formed

New substance(s) formed with different properties
Irreversible (mostly)
Examples: Burning sawdust · Making curd from milk · Rusting of iron · Cooking food

⚠️ Exam Trap — Burning of Candle

Burning of candle = BOTH Physical AND Chemical Change!

Physical: Candle wax melts (reversible)
Chemical: Wax burns to form CO₂ and H₂O (irreversible)
This is a very frequently asked trap question!

💨 Gas Laws

📘 Basis of Gas Laws

For ideal gas, intermolecular force of attraction is negligible. State described by: Pressure (P), Volume (V), Temperature (T), and Amount (n).

Boyle's Law — 1622 | Robert Boyle

Pressure–Volume Relationship

At constant temperature and amount: P ∝ 1/V
If pressure increases → volume decreases (and vice versa)

P₁V₁ = P₂V₂ = k (n, T constant)Boyle's Law Formula | 1622

Charles's Law — 1787 | Charles & Gay-Lussac

Volume–Temperature Relationship

At constant pressure: V ∝ T
If temperature increases → volume increases
Applications: Hydrogen balloon inflation, bread rising in oven

V/T = Constant (P constant)Charles's Law | 1787

Gay-Lussac's Law — 1809 | Joseph Gay-Lussac

Pressure–Temperature Relationship

At constant volume: P ∝ T
If temperature increases → pressure increases

P/T = Constant (V constant)Gay-Lussac's Law | 1809

Dalton's Law of Partial Pressure

Total Pressure = Sum of Partial Pressures

In a mixture of gases, each gas exerts its own partial pressure

P_total = P_A + P_B + P_C + ...Dalton's Law of Partial Pressure

⚠️ Exam Trap — Gas Laws Year + Propounder

Boyle's = 1622 (Robert Boyle) | PV = constant | T constant
Charles's = 1787 | V/T = constant | P constant
Gay-Lussac's = 1809 | P/T = constant | V constant
Ideal Gas Equation combining all: PV = nRT

🎯 High-Frequency BPSC/BSSC Exam Points

Matter = has mass + occupies space; made of molecules & atoms
5 states: Solid · Liquid · Gas · Plasma (4th) · BEC (5th)
BEC: Bose & Einstein (1924); Nobel: Eric Cornell (2001), Rubidium-85
Crystalline solid = Anisotropic + Sharp MP; Amorphous = Isotropic + Range MP
Glass = Amorphous; Quartz = Crystalline
Diamond = Covalent crystalline solid; NaCl = Ionic
Most abundant in Earth's crust = O₂ (46.8%), then Si (27.7%)
Most abundant in atmosphere = N₂ (78%), O₂ (21%)
Tyndall Effect = heterogeneous mixture (particle > 10 nm)
Homogeneous mixture particle size < 1 nm; NO Tyndall Effect
Sublimation examples: Camphor, Dry Ice (CO₂), Naphthalene, Iodine
Butter from milk = Centrifugation
Salt from sea water = Crystallisation
Burning of candle = BOTH Physical & Chemical change
1 mole gas at STP = 22.4 L
1 amu = 1.66056 × 10⁻²⁴ g
Mol. mass of H₂O = 18.02 amu
Boyle's (1622): PV = const (T const) | Charles's (1787): V/T = const | Gay-Lussac's (1809): P/T = const
Boiling point of water = 100°C; decreases with altitude (pressure ↓)
Sea water BP > normal water (dissolved salts raise BP)
Humidity ↑ → Evaporation rate ↓ (opposite of temperature)

📋 Gas Laws Quick Reference

Law	Year	Formula	Constant
Boyle's	1622	P₁V₁ = P₂V₂	T, n
Charles's	1787	V/T = const	P, n
Gay-Lussac's	1809	P/T = const	V, n
Dalton's	—	Pt = P₁+P₂+...	—
Ideal Gas	—	PV = nRT	—

⚠️ Most Common Exam Traps

Glass = Amorphous (NOT crystalline)
Most abundant in crust = O₂ (NOT Si or Al)
Most abundant in atmosphere = N₂ (NOT O₂)
Candle burning = Both physical + chemical
Tyndall Effect = heterogeneous mixture only
BEC = Bose & Einstein (1924); Nobel Prize = Cornell (2001)
Butter separation = Centrifugation (NOT filtration)
Salt from sea water = Crystallisation (NOT evaporation alone)
Humidity ↑ → evaporation ↓ (often confused — humidity opposes evaporation)
PV = const → Boyle's; V/T = const → Charles's

🧪 Matter & States of Matter