metals Flashcards
physical properties of metals
high mp/bp, good conductor of heat and electricity, ductile, malleable
alloys
metal+metal or metal+non-metal
alloys are harder and stronger than metals as it has ions of different sizes arranged in an disorderly manner. This causes particles to be unable to slide pass each other
define alloys
alloys is a mixture of a metal and one or more elements, which may be matal or non-metal
reactivity series
potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, gold
reaction with cold water
alkali + hydrogen
extraction of metals
zinc and metals lying below extracted by heating with carbon
aluminium and above extracted by electrolysis
raw materials
coke, limestone (CaCO3), haematite (Fe2O3)
coke is oxidised by oxygen
C + O2 -> CO2
carbon dioxide then further reacts with carbon to produce carbon monoxide
CO2 + C -> CO
carbon monoxide reduces iron(III) oxide in haematite to molten iron.
3CO + Fe2O3 -> 2Fe + 3CO2
limestone undergoes thermal decomposition
CaCO3 -> CO2 + CaO
silicon dioxide is removed by reacting with calcium oxide
SiO2 + CaO -> SiCaO3
rusting of iron
presence of water and oxygen
prevention of rusting
painting, coating with oil -> prevent being exposed to water and oxygen
why is it important to recycle metal
metals and finite and should be preserved
reduce environment problems as mining causes pollution
saves cost of extracting metals from ore
