presentation kimia (2)

8/6/2019 Presentation KIMIA (2)

1/13

From: 4 Sumaiyah and

4 Siti Aisyah


2/13

The physical properties ofThe physical properties ofpure metalpure metal

properties reasons

high melting and boilingpoint

Strong force ofattraction between the

negative charge andpositive charge

Good conductor of heatand electricity (in solid

and molten state

Presence of free electroncarried heat and

electricity energy


3/13

Malleable and ductile Layer of metal atomcan slide over each

other withoutdisrupting of metallic

bonding. Hence metallicbonds are strong and

flexible

Have high density In solid state the atomin a pure metal are

orderly arranged andclosely packed causespure metal to have high

density


4/13

Metal are ductileMetal are ductile

The orderly arrangement of atom in metal enable theThe orderly arrangement of atom in metal enable thelayer of atom to slide on one another when force islayer of atom to slide on one another when force isapplied as show in figure :applied as show in figure :

Force applied


5/13

Metal are malleableMetal are malleable

There are some imperfections in the orderlyThere are some imperfections in the orderlyarrangement of atom in metal that allow some emptyarrangement of atom in metal that allow some emptyspace in between the atom. When metal is knock ,atomspace in between the atom. When metal is knock ,atomslide. This is why metal are malleable.slide. This is why metal are malleable.

Force

applied


6/13

WHAT ARE ALLOYS?WHAT ARE ALLOYS? Pure metal are usually too soft for most uses. They

also have a low resistance to corrosion. They rushand tarnish easily.

To improve the physical properties of metal, a small

amount of another element (usually metal) is addedto form another an alloy.

An alloy is a mixture of two or more metals(something non-metal) in a specific proportion. For

example: Bronze (90% of copper and 10% of tin) Steel (99% of iron and 1% of carbon)


7/13

The purposes of making alloysThe purposes of making alloysinclude the following:include the following:

Increase the strength

Pure iron is soft and vary malleable. When asmall amount of carbon is added to iron, an alloy,

steal is formed. The more carbon is added, thestronger the steel becomes.

Pure aluminium is light but not strong. With asmall amount of copper and magnesium areadded to aluminium, a strong, light and durablealloy call duralumin is produced.


8/13

Purpose making alloyPurpose making alloy

Improving the resistance tocorrosion

Iron rust easily but stainless steel whichcontains 80.6% of iron, 0.4% of carbon, 18% of

chromium and 1% of nickel does not rush. Theseproperties make stainless steel suitable formaking surgical instrument and cutlery.

Pure copper tarnish easily. When zinc (30%) is

added, the yellow alloy which is known as brassdevelops a high resistance to corrosion.


9/13

Purpose making alloyPurpose making alloy

-Enhancing the appearance

Pewter, an alloy of tin (97%), antimony and copper isnot only hard but also has a more beautiful whitesilvery appearance.

When copper is mixed with nickel to form cupronickel,an alloy that has an attractive silvery, brightappearance is formed which is suitable for makingcoins.


10/13

Composition , properties and usesComposition , properties and usesof alloyof alloy

Alloy Composition Properties Uses

Bronze *90% copper

*10% tin

*hard andstrong

*does notcorrode easily

*has shinysurface

*in the buildingof statues ormonuments

*in the makingof medals,sword andartistic material

Brass *70% copper*30% zinc

*harder thancopper

*in the makingof musicalinstrument andkitchenware


11/13

Steel *99% iron

*1%carbon

*hard and strong *in theconstruction ofbuilding and

bridge*in the buildingof body of carand railwaytrack

Stainless steel *74% iron*8%carbon

*18% chromium

*shiny*strong

*does not rust

*in the makingcultery

*in the makingsurgicalinstrument


12/13

Duralunium *93% aluminium

*3% copper

*3% magnesium*1% manganese

*light

*strong

In the building ofthe body of

aeroplane andbullet trains

Pewter *96% tin

*3% copper

*1% antimony

*lustre

*shiny

*strong

In the making ofsouvenirs


13/13

Arrangement of atom in alloyArrangement of atom in alloy

presentation kimia (2)

Documents