sc13 Flashcards
what are the properties of transition metals
mallable
ductile
good conditions
shiny when polished
often act as catalyst
less reactive than group one and two
are the centre block of the periodic table
what is sacraficial protection
a method of rust prevention
a piece of magensium or sinc is atached to `the object if the metal is less reactibe than them so the oxygen reacts with them
has to be replaced as it corrodes
what is electro plating
coating the surface of one metal with a coat of the other
silver and gold can be electroplated onto base metals to make it cheaper
it can also be used to stop metals from corroding some parts of boats are electroplated in chrome
silver and copper are the best electrical conductors but they tarnish in air so high end equipment is plated in gold
how is electroplating carried out
anode (positivley charged) made from plating metal
cathode (negativly charged) the metal object itself
an electrolyte solution conatining ions of the plating metal
what is galvanising
iron ans steel objects can be protected from rusting by zinc this is galvanising
can be carried out using electroplating or by dipping the object in molten zinc
what is an alloy
a mixture of a metal element with one or more element usually metals
alloy steel are made by adding other relemnts to iron one example of this is stainless steels witch resists rusting
they are often stronger as the structure is distorted
what are the properies of gold and silver
resist corrosion
mallable and ductile
good conductors
both used for electical wiring
gold is more expensive so it is used left often
what are the properties of alluminium
resists corrosion
doesnt conduct electricity
stonger, cheaper and less dense
used to overhead cables
sevral wirs would be wound to make it stronger than a single one
