C1.4 Flashcards
(18 cards)
What is a metal ore?
most metals form compounds
if the compound contains enough metal to make extraction worthwhile, a metal ore
What is oxidation?
gain of oxygen
when metals react with oxygen, often forms an ore the metal has to be extracted from
What is reduction?
reaction that separates metal from oxide- most common form is heating with carbon
involves the loss of oxygen
What are the two methods of extraction?
heating with carbon and electrolysis
based on reactivity series
less reactive than carbon, heating with carbon as carbon oxidised
more reactive than carbon, electrolysis as carbon won’t be oxidised so heating with carbon will have no effect
How does electrolysis remove aluminium from it’s ore?
main ore is aluminium oxide in bauxite
aluminium oxide melted and used as electrode for aluminium extraction
electrolysis decomposes aluminium oxide into aluminium and oxygen atoms
aluminium atoms sink to bottom as molten aluminium metal
What are the useful properties of metals?
malluble
good conductors of electricity
good conductors and insulators of heat
How do properties of metals make them useful?
strength makes them good building material for things like bridges and car bodies
heat conduction so used for things like saucepan bases
electrical conductivity so used for things like electrical wires
What are the properties of aluminium and how is it used?
low density corrosion resistant forms strong, hard alloys malluble lightweight
useful structural material
electrical cables
window frames
aircraft
What are the properties of copper and how is it used?
hard, strong and malluble
high melting point
good conductor of electricity
drawing out into electrical wires
pipes - doesn’t react with water, good for plumbing
What are the properties of gold and what is it used for?
shiny
easy to shape / malluble
unreactive
jewellery
tooth fillings
electric circuits
Why does corrosion happen?
caused by a metal being oxidised so metals higher in reactivity series more likely to corrode as react with oxygen more easily
How does iron rust?
it combines with oxygen and water, forming iron oxide
water bonds loosely, forming hydrated iron oxide
What are the 3 types of steel and their properties and uses?
low carbon (0.1%) - easily shaped, used for car bodies
high carbon (1.5%) - very hard and inflexible, used in blades for cutting tools and bridges
stainless - rust resistant, used for cutlery and containers for corrosive substances
How is stainless steel made?
chromium and sometimes nickel added to steel
What are the differences between pure metals and alloys?
pure metals
regular arrangement
identical sized and shaped atoms
layers of atoms can easily slide over each other so metal soft and bendy
alloys
different sized atoms
disrupts layers and prevents them sliding over each other
metal harder and stronger
What is an alloy?
A combination of metals with different sized atoms
What is a smart alloy?
an alloy containing shape memory property e.g nitinol
if a smart alloy is bent, it will return to it’s original shape once heated
How is nitinol used?
in glasses frames so they can be reshaped if bent
also used for stents in damaged blood vessels
