C1- Chemistry- C3.1 - 3.6 (Metals and their Uses)

?
  • Created by: Em_New99
  • Created on: 19-05-15 16:23

Extracting Metals

Key Points

  • A metal ore contains enough of the metal to make it economic to extract the metal. Ores are mined and might need to be concentrated before the metal is extracted and purified.
  • We can find Gold and other unreactive metals in their native state
  • The reactivity series helps us to decide the best way to extract a metal from its ore. The oxides of the metals below carbon in the series can be reduced by carbon to give the metal element 
  • Metals more reactive than carbon cannot be extracted from their ores using carbon.
  • Metals are chemically extracted from their ores
  • Occasionally some metals are extracted using displacement reactions

Metals must be seperated from their compounds before they can be used

(http://www.edplace.com/userfiles/image/Reactivity%20Series%20ADDED.jpg)

1 of 9

Iron and Steels

Key Points

  • We extract iron from its ore by reducing it using carbon in a blast furnace
  • Pure iron is too soft/ bendy for it to be very useful
  • Carefully controlled quantities of carbon and other elements are added to iron to make alloys of steel with different properties
  • Important examples of steels are- Low carbon steels which are easily shaped; High carbon steels which are very hard; Stainless steels which are resistant to corrosion

.

Steels

  • Are a mixture of different types of steels
  • All of them are alloys of iron and carbon or other elements

.

Alloys and their Properties 

  • Low carbon steel (0.1% carbon)- Easily Shaped- Used for car bodies
  • High carbon steel (1.5% carbon)- Very hard, inflexible- Blades for cutting toold, bridges
  • Stainless steel (Chromium added, sometimes nickel)- Corrosion resistant- Cutlery, cans
2 of 9

Aluminium and Titanium

Key Points

  • Aluminium and titanium are useful as they are low density, strong and resist corrosion
  • Aluminium requires the electrolysis of molten aluminium oxide to extract it as it is too reactive to reduce carbon
  • Aluminium and titanium are expensive becayse extracting them from their ores involves many stages and requires large amounts of energy
  • Both cannot be extracted without their oxides
  • Its expensive to extract as it melts at a high temprature

.

Properties of Aluminium

  • Silvery, shiny. 
  • Light for a metal with low density
  • Excellent conductor
  • Can be easily shaped
  • Relatively reactive
  • Not strong- used for alloys
  • Have a thin layer of oxides on the surface allowing them to resist corrosion
3 of 9

Aluminium and Titanium (Continued)

Uses of Aluminium

  • Drink cans
  • Cooking foil
  • Saucepans
  • High voltage cables
  • Aeroplanes
  • Bicycles

.

Properties of Titanium

  • Silvery-white metal
  • Strong & Resistant to corrosion
  • Has an oxide layer that protects it
  • Denser than aluminium
  • Hight melting point 
4 of 9

Aluminium and Titanium (Continued Again)

Properties of Titanium

  • Bodies of high performance aircrafts & racing bikes (its combination of strength and reltively low density)
  • Parts of nuclear reactors (Withstand high tempratures)
  • Replacament hip joints (Low density & strength)
5 of 9

Extracting Copper

Key Points

  • Most copper is extracted by smelting (roasting) copper-rich ores, although our limited supplies of ores are becoming more scarce
  • Copper can be extracted from copper solutions by electrolysis or by displacement using scrap iron. Electrolysis is also used to purify impure copper, e.g, from smelting
  • Scientists are developing ways to extract copper that use low-grade copper ores. Bacteria are used in bioleaching a pythomining
  • Some metals are more reactive than carbon and therefore need to be extracted by electrolysis

.

Phytomining- Plants absorb copper ions from low-grade copper ore as they grow. This could be from previously discarded waste of copper-rich ores. The plants are then burned an the metals are taken from the ash. 

Bioleaching- Uses bacteria to seperate copper from copper sulfide

6 of 9

Useful Metals

Key Points

  • The transition metals are found in the central block of elements in the periodic table
  • Transition metals have properties that make them useful for building and making things.  For example, copper is used in wiring because of its hight electrical conductivity
  • Copper, gold and aluminium are all alloyed with other metals to make them harder as they are too soft on their own

Transition metals- Good conductors of electricity and energy. Strong but can be bent and hammered into useful shapes. Copper is a good transition metal, can be bent to use as water tanks/ pipes. Does not react as water. 

7 of 9

Metallic Issues

Key Points

  • There are social, economic and environmental issues with exploiting metal ores
  • Plants can remove metals from low-grade ores  The metals can be recovered by processing the ash from burning plants- Pytomining
  • Recyling saves energy and our limited meal ores (and fossil fuels). The pollution from extracting metals is also reduced
  • There are drawbacks as well as benefits from the use of metals in structures

.

Benefits of using metals in consutruction:

  • Copper is a good electrical conductor for wiring- Not reactive so can be made into water pipes
  • Lead can be bent easially so is used to seal joints on roofs
  • Steel is strong for girders and scaffolding
  • Aluminium alloys are corrosion- resistant
8 of 9

Metallic Issues (Continued)

Drawbacks of using metals in construction

  • Iron and steel can rust, severely weakening structures
  • The exploitation of metal ores to extract metals cause pollution & use up earths resources
  • Metals are more expensive thna other materials such as concrete
9 of 9

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Extracting metals /The reactivity series resources »