Bm Assnmnt

8/10/2019 Bm Assnmnt

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Aluminium is the worlds most abundant metal

and is the third most common element

comprising 8% of the earths crust. The

versatility of aluminium makes it the most

widely used metal after steel.

Aluminium is derived from the

mineral bauxite. Bauxite is converted

to aluminium oxide (alumina) via the

Bayer Process. The alumina is then

converted to aluminium metal using

electrolytic cells and the Hall-Heroult

Process.Properties.

Aluminium

1) is a strong, malleablemetalelement.

2) has a low density.

2) is resistant to corrosion.

3) is a good conductorof heat and electricity.4) can be polished to give a highly reflective

surface.
http://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/periodic-table.htmhttp://www.gcsescience.com/e2-element-pure-substance.htmhttp://www.gcsescience.com/pfm35.htmhttp://www.gcsescience.com/ex14.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/ex14.htmhttp://www.gcsescience.com/pfm35.htmhttp://www.gcsescience.com/e2-element-pure-substance.htmhttp://www.gcsescience.com/periodic-table.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htm


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Uses.

1) Low density and strength make aluminium ideal for

construction of aircraft, lightweight vehicles, and ladders.

An alloy of aluminium called duraluminis often used

instead of pure aluminium because of its improved properties.

2) Easy shaping and corrosion resistance make aluminium

a good material for drink cans and roofing materials.

3) Corrosion resistance and low density leads to its use

for greenhouses and window frames.

4) Good conduction of heat leads to its use

for boilers, cookers and cookware.

5) Good conduction of electricity leads to its use

for overhead power cableshung from pylons

(low density gives it an advantage over copper).

6) High reflectivity makes aluminium ideal for

mirrors, reflectorsand heat resistant clothing for fire fighting.
http://www.gcsescience.com/ex30.htmhttp://www.gcsescience.com/pme26.htmhttp://www.gcsescience.com/ex26.htmhttp://www.gcsescience.com/pwav18.htmhttp://www.gcsescience.com/pen11-heat-shiny-reflection.htmhttp://www.gcsescience.com/pen11-heat-shiny-reflection.htmhttp://www.gcsescience.com/pwav18.htmhttp://www.gcsescience.com/ex26.htmhttp://www.gcsescience.com/pme26.htmhttp://www.gcsescience.com/ex30.htm


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PROPERTIES

a good electrical conductor

a good thermal conductor

corrosion resistant

antibacterial

easily joinedductile

tough

non magnetic

attractive colour

easy to alloy

recyclablecatalytic

ALLOYS

. Some copper alloys are:brass: copper + zinc

bronze: copper + tin

cupro nickel: copper + nickel

The alloysare harder, strongerand tougherthan pure

copper. They can be made even harder by hammering them- a process called work hardening.


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Uses.

1) Copper is the main metal for electrical wiring

(compare with aluminium).

2) Copper is malleablewhich makes it an ideal

material for gas pipes and water pipes.Copper is below hydrogen in the reactivity seriesand

therefore it does not react with water.Copper is the metal used

or plumbingin houses.Lead was used for plumbing in the past but has been replaced

by copper because lead compounds in water are toxic.This is an example of a new

material replacing an older one because of the new material's superior properties.

3) Copper is sometimes used for cookware (not common).

4) Copper is mixed with other metals to form alloys.Copper is mixed with zinc to make brassand with tin to make bronze.
http://www.gcsescience.com/ex16.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/r1-reactivity-series-metals.htmhttp://www.cfplumbing.co.uk/http://www.gcsescience.com/e19-safety-symbols-laboratory.htmhttp://www.gcsescience.com/ex31.htmhttp://www.gcsescience.com/ex31.htmhttp://www.gcsescience.com/e19-safety-symbols-laboratory.htmhttp://www.cfplumbing.co.uk/http://www.gcsescience.com/r1-reactivity-series-metals.htmhttp://www.gcsescience.com/r1-reactivity-series-metals.htmhttp://www.gcsescience.com/a42-metal-properties-delocalized-electrons.htmhttp://www.gcsescience.com/ex16.htm


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Physical Properties:

Zinc is a bluish-white, lustrous metal. It is brittle at ambient

temperatures but is malleable at 100 to 150C. It is a reasonable

conductor of electricity.

The density of zinc is 7.140 g/mL, which means the metal will sink

in water and is relatively heavy.

Chemical Properties:

Most zinc production is based upon sulfide ores. These are roasted

in industrial plants to form zinc oxide, ZnO. This may then be

reduced with carbon to form zinc metal.

Zinc burns in air at high red heat with evolution of white clouds of

the zinc oxide.The graphic on the left shows an exothermic reaction of zinc metal

and iodine element reacting to form zinc iodide.


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ZnO + C ==>Zn + CO(ZnO reduced, C oxidised)

ZnO(s) + C(s) ==>Zn(l) + CO(g)

not sure if 2ZnO + C ==> 2Zn + CO2happens?

DOX definition remindersreduction is a process of oxygen loss(or electron gain) and oxidation is a process

e carbon monoxide acts as the reducing agent i.e. it removes the oxygen from the oxide.

e impure zinc is then fractionally distilledfrom the mixture of slag and other metals like lead and cadmium ou

mosphere rich in carbon monoxide which stops any zinc from being oxidised back to zinc oxide.e slag and lead (with other metals like cadmium) form two layers which can be tapped off at the base of the fur

e zinc can be further purifiedby a 2nd fractional distillationor more likely by dissolving it in dilute sulphuric ac

scribed below.

stages

It is dissolved and neutralised with dilute sulphuric acid to form impure zinc sulphate solution.

O + H2SO4==>ZnSO4+ H2O

ZnO(s) + H2SO4(aq) ==>ZnSO4(aq) + H2O(l)

using calamine ore (zinc carbonate) directly:

ZnCO3+ H2SO4==>ZnSO4+ H2O + CO2

ZnCO3(s) + H2SO4(aq) ==>ZnSO4(aq) + H2O(l)+ CO2(g)

Quite pure zinc is produced from the solution by electrolysis. It can be deposited on a pure zinc negative elect

n be purified. The other electrode, must be inert e.g. for laboratory experiments, carbon (graphite) can be use

Zn2+

(aq)+ 2e

==>Zn(s)A reduction process, electron gain, as zinc metal is deposited on the () electrode.

You can't use solid zinc oxide directly because its insoluble and the ions must free to carry the current and

solution.

For more details of the type of electrolysis system used, see purification of copper(just swap Zn for Cu in th

PLEASE note: In the industrial production of zinc by electrolysis(called electrowinning) the negative () ca

zinc deposits) and the positive (+) electrode is made of a leadsilver alloy (PbAg, where oxygen gas is form

Why these particular electrode metals are used in this 'electrowinning' process I'm not quite sure, but alumieffectively inert, and lead and silver are also of low chemical reactivity.
http://www.docbrown.info/page04/Mextractc.htmhttp://www.docbrown.info/page04/Mextractc.htmhttp://www.docbrown.info/page04/Mextractc.htmhttp://www.docbrown.info/page04/Mextractc.htm


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Uses

Zinc is used in alloys such as brass, nickel silver

and aluminium solder. Large quantities of zinc

are used to produce die-castings which are

important in the automobile, electrical and

hardware industries. It is also used extensivelyto galvanise other metals such as iron to

prevent rusting. Zinc oxide is widely used in

the manufacture of very many products such

as paints, rubber, cosmetics, pharmaceuticals,

plastics, inks, soaps, batteries, textiles and

electrical equipment. Zinc sulfide is used inmaking luminous dials and fluorescent lights.


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T e principa ore o ea is ga ena c emica ormu a P S ea su p i e ea II su i e


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T e principa ore o ea is ga ena, c emica ormu a P S ea su p i e ea II su i eThere is also the less commonlead ore cerussite, chemical formula PbCO3, lead carbonate(lead(II)

carbonate)

The crushed ores are concentrated by a technique known as froth flotation.

The ores are roasted to drive off unwanted water and convert them to a more suitable chemical form e.g.

lead oxide, for reduction to lead metal. The poisonous acidic gas sulfur dioxide (sulphur dioxide) is

formed.Roasting galena in air converts the lead sulphide into lead(II) oxide ...

lead(II) sulfide + oxygen ==> lead oxide + sulfur dioxide

2PbS + 3O2==> 2PbO + 2SO2

2PbS(s) + 3O2(g) ==> 2PbO(s) + 2SO2(g)

... but harmful and polluting sulfur dioxide is made in the process, which must be dealt with!

Roasting cerussite coverts the lead carbonate into lead oxide ...

lead(II) carbonate ==> lead(II) oxide + carbon dioxidePbCO3==> PbO + CO2

PbCO3(s) ==> PbO(s) + CO2(g)

... an example of a thermal decomposition

The more concentrated lead oxide can then be reduced in a coke fired blast furnace ...

lead(II) oxide ==> lead + carbon dioxide

2PbO + C ==> 2Pb + CO2

2PbO(s) + C(s) ==> 2Pb(l) + CO2(g)

... the lead oxide is reduced (oxygen loss) and the carbon/coke reducing agent is oxidised (oxygen gain)

in the smelting process.

... as in the blast furnace from iron, the liquid lead can be drained off from the lead smelter.

The above balanced equations, are a simplification of what can be quite complicated chemistry, BUT

they do adequately describe and illustrate the chemical processes for obtaining lead from its ores.

The overall process from lead ore to very pure lead is quite complicated and lead ores contain othervaluable metals like silver, so there more stages in the process than are described here.


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Lead is very resistant to corrosion - lead pipes

from Roman times are still in use today

and it is often used to store corrosive liquids.Great quantities of lead, both as the metal and

the dioxide, are used in batteries.

Lead is also used in cable covering, plumbing

and ammunition.

Tetraethyl lead is used as an anti-knock agent

in petrol, and as an additive in paints.The use of lead in plumbing, petrol and paints

has been reduced in the past few years

because of environmental concern, as lead is a

cumulative poison and is thought to affect

brain development and function, especially in

young children.Lead is an effective shield around X-ray

equipment and nuclear reactors.

Lead oxide is used in the production of fine

crystal glass.


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