Metals Details/Definitions Flashcards
General physical properties of metals
-Good conductors of heat/electricity
-Malleable
-Ductile
-High melting/boiling points
-Sonorous(makes bell-like sounds when struck)
Metal + Acid →
Salt + Hydrogen
Metal + Oxygen →
Metal Oxide
Metal + Cold Water →
Metal Hydroxide + Hydrogen
Metal + Steam →
Metal Oxide + Hydrogen
Factor that determines if a metal reacts in cold water or steam
The reactivity of the metal(more reactive metals can react fine in cold water, but other less reactive metals like copper only react in steam)
Uses of aluminium
-Manufacture of aircraft(due to strength and low density)
-Manufacture of overhead electrical cables(due to strength and good electrical conductivity)
-Used in food containers(due to good resistance to corrosion)
Uses of copper
-Electrical wiring(because of its good electrical conductivity and ductility)
-Utensils
Uses of zinc
-Galvanizing
-Production of brass
Uses of steel
-Car bodies and machinery
-Production of stainless steel
Alloy
a mixture of a metal and other elements
Brass is a mixture of…
copper and zinc
Stainless steel is a mixture of…
iron, chromium, nickel and carbon
Benefit of alloys
They can be harder, stronger and more useful than the pure metals
Uses of stainless steel
Cutlery(due to hardness and resistance to rusting)
How alloys can be harder and stronger than pure metals
The different sized atoms in alloys mean that the layers can no longer slide over each other
Reactivity series
-Potassium
-Sodium
-Calcium
-Magnesium
-Aluminium
-Carbon
-Zinc
-Iron
-Hydrogen
-Copper
-Silver
-Gold
Why aluminium seems unreactive(even though it is)
Aluminum often reacts with oxygen in the air to form an ‘aluminium oxide coating’, which is unreactive and acts as a protective layer and prevents aluminium from reacting with other elements
Result of reaction of potassium with cold water
Violent reaction with cold water
Result of reaction of sodium with cold water
Violent reaction with cold water
Result of reaction of calcium with cold water
Quick reaction with cold water
Result of reaction of magnesium with steam
Moderate reaction with steam
Result of reaction of magnesium with dilute hydrochloric acid
Vigorous reaction with dilute hydrochloric acid
Result of reaction of zinc with dilute hydrochloric acid
Moderate reaction with dilute hydrochloric acid
Result of reaction of iron with dilute hydrochloric acid
Moderate reaction with dilute hydrochloric acid
Result of reaction of copper with dilute hydrochloric acid
No reaction
Result of reaction of silver with dilute hydrochloric acid
No reaction
Result of reaction of gold with dilute hydrochloric acid
No reaction
Conditions required for the rusting of iron and steel to form hydrated iron(III) oxide
-Must be in contact with oxygen
-Must be in contact with water
Common barrier methods(of metals)
-Painting
-Greasing
-Coating with plastic
-Galvanizing(eg. with zinc)
Why barrier methods prevent rusting
They prevent the metals from coming into contact with oxygen or water
Galvanising
the process of coating iron or steel in a protective layer of zinc
Sacrificial protection
The protection of iron or steel against corrosion by using a more reactive metal to coat them
(In terms of difficulty of extracting from ore)The higher a metal is in the reactivity series…
the harder it is to extract from its ore(as more reactive metals ‘like’ to stay in a compound more)
Extraction of iron from hematite in the blast furnace
-The burning of carbon(coke) to provide heat and produce carbon dioxide
-The reduction of carbon dioxide to carbon monoxide
-The reduction of iron(III) oxide by carbon monoxide
-The thermal decomposition of calcium carbonate/limestone to produce calcium oxide
-The formation of slag
Main ore of aluminium
Bauxite
Aluminium is extracted by…
electrolysis
Symbol equations for the extraction of iron from hematite
C + O₂ → CO₂
C + CO₂ → 2CO
Fe₂O₃ + 3CO → 2Fe + 3CO₂
CaCO₃ → CaO + CO₂
CaO + SiO₂ → CaSiO₃
Role of cryolite
-Decreases the melting point of aluminium oxide(bauxite)
-Acts as a solvent for aluminium oxide(bauxite)
Why the carbon anodes(in electrolysis) must be regularly replaced
The carbon anodes burn away in oxygen(and hence need to be regularly replaced)
Bronze is a mixture of…
copper and tin
