Class 8 Chemistry CBSE

Chemistry Concept Maps Class VIII • Synthetic Fibres and Plastics • Metals and Non-Metals • Coal and Petroleum • Combustion and Flame

Magnetic recording tapes , video cassettes curtains

1. Absorbs less water 2. Strong , light,elastic and resists wrinkles

Uses

Light, elastic and high tensile strength

Properties

Properties

Cotswool, polycot, terrywool

Blended

Umbrellas, parachutes, socks Uses

Polyester (terylene or mylar or dacron) Nylon

Wool

FIBRES

Natural

Acrylic (Orlon or Acrilan)

Synthetic

A thread or filament from which a cloth is made

Silk

Uses

Cotton

Semi synthetic Properties

Formation

Air and water proof

Rayon (Artificial silk) Shirt, ties, lining etc.

Uses

Properties 1. Absorbs moisture 2. Lustrous and resembles silk

Uses

Warm, soft and light

Sweaters, socks

Spandex (Lycra)

Koroseal

Viscose process

Properties

Uses Rain coat, bathroom curtains

Properties High elasticity and stretchable

Swimming costumes caps, T-Shirts

(Hard and unbreakable) (decorative objects, dinner set) Uses Polythene polymer of ethene

PVC polymer of vinyl chloride

Properties

Monomer (Melamine & formaldehydae)

Melamine Monomers (Phenol & formaldehyde)

PS polymer of styrene

Thermosplastic

On the basis of their reaction to heat

Thermosetting plastic

Bakelite

Properties (Hard, stiff and insulator)

Uses PET (polymer of ethylene glycol & terphthalic acid)

(combs, switches, table top laminates phonograph recrods)

PP (polymer of propylene)

On the basis of arrangement of monomer unit

Types

Linear PVC,HDPE

Branched LDPE

Cross-linked Bakelite,Melamine

Solutions

Reduce, Reuse, Recycle and Recover

PLASTICS

Problems

Polymeric material which can be easily moulded or set into any desired shape and size

• Soil and water pollution • On burning produces toxic gases • Death of animals

Properties

Poor conductor of heat and electricity, insoluble in water non-reactive, strong, durable, light

2NaBr (aq) + Cl2(g) P4 + NaOH + 3H2O no reaction Does not-metal displaces less reactive non-metal from its salt solution

More reactive non-metal displaces less reactive non-metal from its salt solution

Reaction with salt solution

2NaCl + Br2(g) NaH2PO2 + PH3

Acidic CO2, SO2

Oxides

reaction water & dilute acid

Chemical properties

Reaction with oxide

Reaction with oxygen Neutral NO, N2O, H2O Oxides

have 4 to 8 valence electrons

Reaction with base

Electronic configuration

Reaction P4 + 3NaOH + 3H2O

Low densities except I2, diamond Load conductor of heat & electricity except allotrope of carbon

Electro negative nature

NON-METAL

Uses

A not ductile

Brittile excpet (allotrope of carbon i.e. diamond)

Physical properties

Low m.p. & b.p except C,B,Si

Soft and have low tensile has strength except carbon

Not sonorous

not lustrous except graphite and iodine

Not malleable

State

(C,S,I2) etc. solid

O2,H2,N2 etc Gas

(Br2) liquid

3NaH2PO2 + PH3

2NaCl + H2

Na + 2HCl Al + 3H2SO4

Zn(s) + CuSO4(aq)

Reaction with water

Reaction with dilute acid

Al2(SO4)3 + H2

ZnSO4(aq)

Hydroxide Na(s) + H2O

NaOH + 1/2H2

MgO + 2H2O

Mg(OH)2 + H2

Oxides Displacement reaction

Reaction with salt solution

4H2O

Fe(s) + 4H2O

Basic oxide Na2O, CaO Na

Li K Ba Na Ca Mg Al Zn Fe Sn Pb H Cu Hg Ag Pt Au

+

Na + e

–

Reducing agent

Chemical properties

Reaction with oxygen Amphoteric oxide ZnO, Al2O3

ReactivitySeries

METAL

Uses

Good conductor of heat & electricity except lead Cl

Electronic configuration i d 3 electrons invalence shell Hard & posses high tensile strength excpet Na,K

Chemical properties

Lustrous

High density Malleable Sonorous

Ductile

High melting & boiling point except CS, Ga, Fr

Properties

Manufacture of H2 required in fertilizers

Heating, cooking heat source

Thick, black liquid with unpleasant smell

Properties

All carbon fource carbon used as filler in manufacture of tyres

Domestic and industrial fuel

Chemical substance to repare dyes,explosives, pain perfumes

Gases and high calorific value

Uses

Coal tar

Coal gas

Cleam fuel Gases and high calorific value

Uses

Natural gas (55 kJ/g)

Properties

Uses Products obtained on destructive distillation

Coke

Ammonical liquor

Properties Leaver no residue no poisonon agases

Deposists

Uses

Tripura, Rajasthan, Maharastra& Krishna Godavari delt

Properties

Resisdual orl

Bitmunous Faraffin

Lignite Types

Petroleum

FOSSIL FUEL

Coal

Lubrating oil

Peat

Food oil

Anthracite

Deposists

Uses Fuel synthetic petrol and synthetic natural gas organic compounds obtained

Formation

Deposits

Disel oil Kuwat, sandi Arabia, Iraq china, USA Rusia Likya etc.

Jharkhand mp & wb

Concentration

Kerosene

Sand

Type

Petrol Petroleum gas

Nonrenewable

Renewable

Exhaustible Natural resources

Petrol

Diesel

2H2O + Heat

No resisdue H2 + O2

Low ignition temperature and costlier Liquid

Hydrogen

Highest calorific value (150 kJ/g)

Coal

Wood

CH4 + C2H6 + C3H8 Solid

Types

Gases

LPG

Colourless, odourless and inflammable gas Calorific value 50 kJ/g

CNG Slow

Low ignition temperature and cheaper

Fuel

Rapid

No resisdue and clean fuel CO2 + H2O + heat CH4 + O2

Calorific value 55 kJ/g Complete

Spontaneous Nonluminous zone (hottest)

Types Incomplete

Inner dark zone

Yellow Luminous zone (moderately hot)

More light

Luminous

COMBUSTION

Combustible substance Supporter O2 Attainment of ignition temperature

FLAME

Conditions required Unburnt carbon causes respiratory diseases CO causes suffocation, etc

Unsufficient oxygen

Products and their effects

SO2, NO2 causes acid rain

Non Luminous CO2 causes global warming

Excess of oxygen

Black soot

Blue

Less light No residue