English std 8-3- rocks

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ASIA

SCIENCESCIENCEStd:- VIIIStd:- VIII

Rocks, Minerals, Rocks, Minerals, and Metalsand Metals

Graphics & Written ByGraphics & Written By :- :- Pradip B. PatelAsia English School

1,sunrise park, opp, Drive in road

TheltejAhmedabad – 38 00 54

Chapter -3 -3Rocks, Minerals and MetalsRocks, Minerals and Metals

qDko, qinjo Ane 2atuAoqDko, qinjo Ane 2atuAo

SHALESHALESHALESHALE

LIMESTONELIMESTONELIMESTONELIMESTONE

SANDSTONESANDSTONESANDSTONESANDSTONE

FOLDED ROCK FORMATIONFOLDED ROCK FORMATIONFOLDED ROCK FORMATIONFOLDED ROCK FORMATION

GASGASGASGAS

WATERWATERWATERWATER

OILOIL

Rocks are found on the Rocks are found on the crust of the earth and crust of the earth and made up of mineral made up of mineral

IRON ROCKIRON ROCK

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Some are coarse grained as granite. Clay has much fine grains that we cannot see them separately. If you closely examine a piece of granite, you will find that it is made up of a number of substances under a magnifying lens or a microscope. Substances which assemble together to form rocks are called mineralsminerals.. Minerals are naturally occurring inorganic substances.

Std - 8th chapter – 3Rocks, Minerals & Metals

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Magnifying lens

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1.02.12.6

2.8

3.6

5.1

8.2

27.8

46.8

OXYGEN (O2)

SILICON ( Si)

ALUMINIUM ( Al)

IRON ( Fe)

CALCIUM (Ca)

SODIUM (Na)

POTASSIUM (K)MAGNESIUM (Mg)OTHERS

The Earth’s CrustThe Earth’s Crust

The average thickness of earth crust is 35 km under the continents and 10 km under the oceans.

Three forth of the earth crust is made just of two non metals.(1) Oxygen (2) Silicon.

Remainder of the crust consists of mainly six metals (1) Aluminum (most abundant) (2) Iron (3) Calcium (4) Sodium (5) Potassium(6) Magnesium.


MineralsMinerals PercentagePercentage

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Pressure

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Heat, pressure & chemical changes

Melts, cools and becomes solid

Metamorphic RocksMetamorphic Rocks

Sedimentary RocksSedimentary Rocks

Heat,pressure & chemical change

Weathering, erosion and becomes solid

Igneous RocksIgneous Rocks


Magma

© PRADIP PATELIGNEOUS ROCKSIGNEOUS ROCKS

Magma Magma

Meaning:- Word derived from the latin word ‘ignis’ meaning fire. First rock to appear on the earth’s surface.

Formation:- Formed by the cooling and solidification of extremely hot molten material, magma below the earth crust.

This magma pushes its way through earth’s crust with high pressure to form igneous rocks.

Large part of west central part of our country called the Decean Plateau.

Granite is formed when the rising magma solidifies before reaching the surface in the form of coarse grained.


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SEA

By the deposition fo sediments SEDIMENTS are broken down particles of existing rocks which are deposited layers by layers by flowing water or wind in the sea along with dead plants and animals.

All this are neatly preserved in the sediments. The process goes on for millions of years and the resultant rocks are called

Sedimentary rocks. Sedimentary rocks contains the relics of plants & animal known as Fossils. They harden with age. Thickness of overlaying layers are usually soft.

Small plant, animals are depositing

layer by flowing water

or wind

SEDIMENTARY ROCKSSEDIMENTARY ROCKS


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PRESSURE

METAMORPHIC ROCKSMETAMORPHIC ROCKS

HEAT & PRESSUREHEAT & PRESSURE FORMATION :- When igneous or sedimentary rocks are subjected to intense heat, compression or fluid injection the physical & chemical properties changes which results in metamorphic rock


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Naturally occuring inorganic substances with specific composition.

Substance which assemble together to form rocks are called Minerals.

There are about 2000 distinctive minerals.

A mineral made of atom of a single element or of more than one

elements.

It is identified by its physical properties such as colour, lustre,

hardness, specific gravity and cleavage.

MineralsMinerals

GaeilnaGALENA ( PbS )

meGne3a{3MAGNETITE ( Fe3O4 )

Paa{ra{3PYRITE ( FeS2 )

Asbestos has a shimmering silky lustre.Abrq

Have metallic lustre.


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MineralMineral UsesUses

1 Quartz Glass, Sandpaper, Telephone, Radio, Watches.

2 Feldspur Porcelain, China dishes.

3 Mica Insulator in Electrical appliances: irons, motors, toasters

4 Rock salt In food, food preservation, raw material for chemical industry.

5 Gypsum Cement, Plaster of paris

6 Talc Talcum powder

7 Pitch blend Nuclear fuel

8_ Monazite Nuclear fuel for breeder reactor.

Non-metallic minerals and their usesNon-metallic minerals and their usesStd - 8th chapter – 3

Rocks, Minerals & Metals

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IdentifyIdentify uses of uses of mineralmineral

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Chemical Chemical formulaformula

MetalMetal Type of oreType of ore

Haematite Fe2O3 Iron Oxide

Iron Pyrite FeS2 Iron Sulphide

Copper Pyrite CuFeS2 Copper Sulphide

Copper glance Cus / Cu2S Copper Sulphide

Bauxite Al2O3 . 2H2O Aluminium Oxide

Galena PbS Lead Sulphide

Litharge PbO Lead Oxide

PyrolusitePyrolusite MnO Manganese Oxide

Some common oresSome common oresStd - 8th chapter – 3


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Waste gas

SLAGCalcium silicate

MOLTEN IRONBLAST FURNACEBLAST FURNACE

3000 C.5000 C.7000 C.9000 C.

10000 C.12000 C.

19000 C

Cone & Glass shape

HOT AIR Middle portion of the furnace is known as BOSCH.its width is

about 7-8 meters.

Blast furnace total Blast furnace total height is about 30-40 height is about 30-40 meters.meters.

Out side portion is made up of steel, and inside portion is

lined with fire bricks.

FeO + CO Fe + CO2

Iron oxide, limestone & cokeCaCO3 heat CaO + CO2

CaO + SiO2 CasiO3

Impurities slagFe2O3 + C 2 Fe3O4 + COFe3O4 + CO 3 FeO + CO2


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Pig ironPig iron Wrought ironWrought ironIt contains 4 to 5 percent carbon and other impurities such as sulphur, phosphorous, silicon and manganese.

It is the purest commercial form of iron free from carbon.

The presence of impurities lowers the melting point.

It is malleable.

It is brittle. It is ductile and stronger.

It can be melted and moulded into various shapes such as pipes, storage tanks, bath-tubes, stores, cylinder and other shapes.

It can not used for molded articles.

Sheets and wires cannot be made of pig iron.

It can be hammered into sheets and drawn into wire or given desired shapes.

Pig ironPig iron && Wrought ironWrought ironStd - 8th chapter – 3


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Waste gas

Iron oxide, lime stone& coke

Hot air.

SLAG

This way molten iron is directly taken to

steel plants.

The concentrated ore along with coke (c) and limestone are added to a blast furnace. Blasts of hot air at about 19000 C are blown into the furnace lined with fire bricks. The coke reduces the ore to metallic iron. The molten iron collects at the bottom of the furnace. Limestone on heating decomposes to calcium oxide and carbon dioxide. Calcium oxide reacts with the sand and forms a slag (calcium silicate)

3000 C.5000 C.7000 C.9000 C.

10000 C.12000 C.

19000 C

BLAST FURNACEBLAST FURNACE


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Impure copper anode

Impurities

Copper sulphate solution

Electric supply

+

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Pure copper cathode

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