Flashcards · 5070 · Topic 9

Metals flashcards

28 cards on Topic 9, subtopics 9.1 to 9.6. Pick a subtopic or study them all.

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General physical properties of metals: Good conductors of heat and electricity, malleable, ductile, and usually high melting and boiling points.
General physical properties of non-metals: Poor conductors of heat and electricity, brittle when solid, and usually low melting and boiling points.
metal + dilute acid → metal + oxygen →: salt + hydrogen metal oxide

Aluminium: two uses and the property behind each: Aircraft parts — low density. Food containers — resistance to corrosion.
Copper: a use and the properties behind it: Electrical wiring — good electrical conductor and ductile.
Aluminium in overhead electrical cables: which properties?: Low density and good electrical conductivity.
Copper in electrical wiring: which properties, and what does ductile mean?: Good electrical conductivity and ductility. Ductile means it can be drawn out into wires.

Alloy: A mixture of a metal with other elements.
What is brass made from?: Copper and zinc.
Stainless steel: composition and a use: Iron mixed with chromium, nickel and carbon. Used for cutlery, because it is hard and resists corrosion.
How do the hardness and strength of an alloy compare with the pure metal?: Alloys can be harder and stronger than the pure metals.
Explain why an alloy is harder than the pure metal: The different-sized atoms disrupt the regular layers, so the layers cannot slide over each other as easily.

The reactivity series (most to least reactive), with carbon and hydrogen: Potassium, sodium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold.
Which metals react with cold water, and which only with steam?: Cold water: potassium, sodium, calcium. Steam: magnesium (very slow with cold water), zinc and iron.
Will magnesium displace zinc from zinc sulfate solution?: Yes. Magnesium is more reactive than zinc, so it gives up electrons more readily and displaces it.
Why does aluminium seem unreactive?: It is covered by a thin, protective layer of aluminium oxide.

What two things are needed for iron to rust?: Water and oxygen.
Rust: Hydrated iron(III) oxide.
Barrier methods of rust prevention: Painting, greasing (oiling) and coating with plastic — they keep out water and oxygen.
Sacrificial protection: Attaching a more reactive metal (such as zinc or magnesium) to iron. It corrodes instead of the iron.
Galvanising, and why it beats tin plating: Coating iron with zinc. It is a barrier and also sacrificial, so iron is still protected if scratched. Tin is less reactive than iron, so scratched tin plate rusts faster.

How a metal’s position in the reactivity series decides its extraction method: More reactive than carbon: electrolysis. Less reactive than carbon: reduction by heating with carbon.
Raw materials of the blast furnace: Hematite (iron ore), coke (carbon), limestone and hot air.
What reduces iron(III) oxide in the blast furnace?: Carbon monoxide.
Main ore of aluminium, and how aluminium is extracted: Bauxite. Aluminium is extracted by electrolysis.
Equation for the reduction of iron(III) oxide in the blast furnace: Fe₂O₃ + 3CO → 2Fe + 3CO₂
How limestone removes impurities in the blast furnace: CaCO₃ → CaO + CO₂, then CaO + SiO₂ → CaSiO₃ (slag).
Role of cryolite in aluminium extraction: Aluminium oxide is dissolved in molten cryolite, which lowers the operating temperature and improves conductivity.