9 Metals Flashcards
Uses of aluminium
Manufacture of aircraft: low density
Manufacture of overhead
electrical cables: low density
and good electrical conductivity
Food containers: resistance to corrosion
Uses of copper
electrical wiring because of its good electrical conductivity and ductility
alloy
mixture of a metal with other elements
Brass
Alloy - mixture of copper and zinc
Stainless stell
Alloy - mixture of iron and elements such as chromium, nickel and carbon
Why are alloys sometimes more useful than pure metals?
Alloys can be harder and stronger than the pure metals
Use of stainless steel
Cutlery: hardness and resistance to rusting
Why are alloys harder and stronger than pure metals?
the different sized atoms in alloys mean the layers can no longer slide over each other as easily.
Order of reactivity series
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
ZInc
Iron
Lead
Hydrogen
Copper
Silver
Gold
Potassium reaction with cold water
Potassium + water –> potassium hydroxide + hydrogen
2K + 2H2O → 2KOH + H2
Sodium reaction with cold water
Sodium + water –> sodium hydroxide and hydrogen
2Na + 2H2O → 2NaOH + H2
Calcium reaction with cold water
Calcium + water –> calcium hydroxide + hydrogen
Ca + 2H2O –> Ca(OH)2 + H2
Alkali metal + water –>
alkali metal hydroxide + hydrogen
Metal + steam –>
Metal oxide + hydrogen
magnesium reaction with steam
Magnesium + steam –> magnesium oxide + hydrogen
When does a metal not reactive with acid?
When the metal is less reactive than hydrogen
Metal + acid –>
Salt + hydrogen gas
Zinc reaction with hydrochloric acid
Zinc + hydrochloric acid –> zinc chloride + hydrogen
Zn + HCl –> ZnCl2 + H2
Magnesium reaction with hydrochloric acid
Magnesium + hydrochloric acid –> magnesium chloride + hydrogen
Mg(s) + 2HCl –> MgCl2 + H2
Copper reaction with hydrochloric acid
No reaction. Copper is less reactive than hydrogen in the reactivity series.
What does the reactivity of a metal mean?
a metals tendency to form postive ions. The more reactive a metal is, the more easily it forms positive ions.
What metal is the reducing agent during a displacement reaction?
More reactive metals are the reducing agent.
why does aluminium seem unreactive?
metal reacts with oxygen initially to form Al2O3. this oxide forms a protective layer and prevents aluminium from reacting with water, acids, etc.
Describe the extraction of iron in a blast furnace
1) the burning of carbon (coke) to provide heat
and produce carbon dioxide
2) the reduction of carbon dioxide to carbon monoxide
3) the reduction of iron(III) oxide by carbon monoxide
4) the thermal decomposition of calcium carbonate /limestone to produce calcium oxide
5) the formation of slag
What is aluminium ore called and how is it extracted
Bauxite - extracted by electrolysis
the symbol equations for the extraction of iron from hematite
1) C + O2 –> CO2
2) C + CO2 –> 2CO
3) Fe2O3 + 3CO –> 2Fe + 3CO2
4) CaCO3 –> CaO + CO2
5) CaO + SiO2 –> CaSiO3
Role of cryolite in extraction of aluminium from aluminium oxide
decreases the melting point (to 950C) and increases the conductivity of molten aluminium oxide
Why do the carbon anodes nead to be placed regulary during aluminium ore extraction?
Oxygen forms at the anode and reacts with the carbon anode to form carbon dioxide - corroding the anode.
half equation of the extraction of aluminium oxide
Al+3(aq) + 3e- –> Al(s)
Oxidation half equation of the extraction of aluminium oxide
2O-2(aq) –> O2(g) + 4e-
Conditions required for the rusting of steel and iron to form hydrated iron(III) oxide
water and oxygen (which we see as rust)
Common barrier methods to prevent rusting
Painting, greasing, and coating with plastic
How do barrier methods prevent rusting?
By stopping the water and oxygen getting to the iron
what is zinc galvanisation
applying a protective zinc coating to iron or steel to prevent rusting.
