Post on 01-Apr-2015
transcript
eymmcl2003
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Why does scratched, tin plated iron rust faster than
non-plated iron?
answer
Electrons flow from iron to tin because tin is below
iron in the electrochemical series
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From magnesium to iron
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Magnesium provides iron with Magnesium provides iron with sacrificial protectionsacrificial protection. In which . In which direction do electrons flow?direction do electrons flow?
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Which metal is used toWhich metal is used to galvanisegalvanise iron?iron?
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zinczinc
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Which metal RUSTSWhich metal RUSTS??
answer
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iron
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Give an example of how Give an example of how iron can be physically iron can be physically
protected.protected.
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answer
Paint, grease, tin-Paint, grease, tin-plate, electroplate, plate, electroplate,
galvanising, coat with galvanising, coat with plasticplastic
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How does a How does a physical barrierphysical barrier protect iron against rusting?protect iron against rusting?
Barrier to water and air Barrier to water and air (oxygen)(oxygen)
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WhichWhich terminalterminal of a of a battery protects iron battery protects iron
from rusting?from rusting?answer
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negativnegativee
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What name is given to theWhat name is given to the coating of iron withcoating of iron with zinczinc??
galvanisgalvanisinging
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Chromium plated steel rusts Chromium plated steel rusts quicklyquickly when scratched. when scratched.
Compared to iron is Compared to iron is chromium more reactive or chromium more reactive or
less reactiveless reactive..
Less reactive
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Why does salt Why does salt speedspeed up corrosion?up corrosion?
Salt is an electrolyte
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How does How does salt salt and and acid acid rainrain affect corrosion? affect corrosion?
Speeds it up
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What is the test for What is the test for FeFe2+2+ ions? ions?
Ferroxyl indicatorFerroxyl indicatorturns blueturns blue
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What What twotwo conditions are conditions are required required
for rusting to take place?for rusting to take place?
Water and oxygen
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What type of reaction takes What type of reaction takes place when a metalplace when a metal
corrodescorrodes??
oxidation
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What is corrosion?What is corrosion?
A chemical reaction involving a metal changing from an
element to a compound
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WhichWhich ionion is formed when is formed when water water
and oxygen gain electrons? and oxygen gain electrons?
OHOH-- (hydroxi(hydroxi
de)de)
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Which ironWhich iron ion ion is is formed formed
when iron rusts?when iron rusts?
FeFe2+2+
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