Chapter 10 Flashcards
Physical properties of metals
high conductivity (heat and electricity), malleable, ductile, high melting and boiling point
Chemical properties of metals
metals react with acids to produce salt and hydrogen, a displacement reaction occurs with acids, and metals react with oxygen to produce a metal oxide
Why are alloys more used than pure metals?
Pure metals are more malleable and less tough than alloys. This is because the uniform layers can slide over each other while strange different sized atoms in alloys make it more difficult for the layers to slide across each other, making it less malleable.
Identify the difference in alloy diagrams and pure metal diagrams
idk just find it out for yourself
Reactivity series and their reactions
potassium, sodium, lithium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver and gold. When you go up, the reaction of water and steam, reduction with carbon and acid increases.
If 1 does not react with 2….
….than anything above 1 will react with 2
reactivity of metals
the tendency of a metal atom to lose its electrons and become a positive ion
Describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction in displacement reactions
In displacements reactions, they occur as one metal, higher in the reactivity series and therefore more reactive, displaces another metal. this can be in oxides, aqueous ions etc. example: aluminium + iron(III) oxide → iron + aluminium oxide
heat and metal hydroxide
metal hydroxide —> metal oxide + steam (only zinc iron and copper decompose, the rest are too stable)
heat and metal nitrate
metal nitrate —> metal oxide + nitrogen dioxide + oxygen (if metal is zinc, iron or copper)
metal nitrate —> metal nitrate + oxygen
unreactive aluminium
Caused as the outer layer of aluminium reacts with oxygen to form aluminium oxide. This acts like a very unreactive layer of metal oxide which coats the aluminium
Describe obtaining metals from their ores by relating the elements to the reactivity series
Metals are found as ores and are bound to other elements. To obtain pure metal, we must displace these other elements. For less reactive metals, this process is relatively simple. As zinc, iron and copper are less reactive than carbon, it is possible to obtain these metals in a pure state just by heating them strongly in the presence of carbon. For more reactive metals, electrolysis needs to take place.
state the essential reactions in the extraction of iron from hematite
- carbon + oxygen —> carbon dioxide
- carbon dioxide + carbon —> carbon monoxide
- iron oxide + carbon monoxide —> iron + carbon dioxide
- iron oxide + carbon —> iron + carbon monoxide
Describe the conversion of iron into steel using basic oxides and oxygen
Oxygen is blown into the molten iron. It reacts with the excess carbon to form CO_2 and CO which leave. It also reacts with the impurities in iron to form acidic oxides later removed with calcium oxide. The amount of oxygen blown into the molten iron is controlled to determine the final carbon content correct to produce steel.
Describe the essential reactions in the extraction of iron from hematite
Iron ore, limestone and coke added to the blast furnace. Hot air moves to the top, formed from carbon combing with oxygen in an exothermic reaction. CO formed by reaction between oxygen and coke. CO and some carbon reduce iron oxide to iron by taking oxygen with them. Molten iron runs out from the bottom of the blast furnace
Aluminium is extracted from the ore bauxite by….
…..electrolysis.
advantages of recycling metals, limited to iron/steel and aluminium
- cheaper, as electrolysis is expensive af
- reduces environmental impact from mining and the extraction of new metals
- less waste produced so less landfill
- more sustainable - does not use up the finite resources
- less energy required compared to electrolysis
disadvantages of recycling metals, limited to iron/steel and aluminium
- collection and transportation to recycling centres needed, therefore more air pollution
- sorting requires a lot of time and labour
- energy saving can not truly be determine as it varies between metals
Describe in outline, the extraction of zinc from zinc blende
Zinc blende is heated to form zinc oxide, which is then reduced with carbon monoxide or its reduced with sulphuric acid and then electrolysed to produce pure zince
Describe the extraction of aluminium from bauxite including the role of cryolite and the reactions at the electrodes
aluminium, due to its position in the reactivity series, needs to be electrolysed. However, it firstly needs to be dissolved in cryolite (as molten aluminium would be too impractical and expensive to electrolyse) beforehand. afterwards however, pure aluminium is formed at the cathode and oxygen at the anode.
Name the uses of aluminium
the manufacture of aircraft because of its
strength and low density and food containers because of its resistance to corrosion
Name the uses of copper
electrical wiring as it is a very good conductor and can bend easily and in cooking equipment because it is a good conductor of heat and therefore, can warm up food more quickly.
Name the uses of mild steel
Car bodies and tough machinery as it is very tough, ductile, malleable and has a good tensile strength
Name the uses of stainless steel
Cutlery and chemical plants as it is resistant to corrosion
