Qualification > Sciences

CHEM PAPER 3 PLEASEEE HELPPP

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J.Darren:

--- Quote from: ~$VJ DJ$~ on June 06, 2010, 12:25:58 pm ---What is, and what are the diffrences between sacrifical protection and cathodic protection????

help me please

--- End quote ---
Sacrifical protection is when you coat steel with zinc. Zinc, the more reactive metal, gets corroded and forms Zinc ions (i.e. Zinc gets oxidised). The iron accepts electrons onto its surface, since it does not lose electrons, it is not corroded. Sacrifical protection does not require electricity, and the steel does not need to be fully coated with Zinc.

Cathodic protection involves an inert electrode (usually Titanium), it needs electricity (i.e a power supply). Oxidation occurs at the inert electrode , electrons flow through the external circuit to the steel cathode.

~$VJ DJ$~:
thx really helpful

ColdStorm:
Excuse Me Guys  How Many Marks Can i Afford To Still Be able To Get An A Or An A*
need quick REplies please :P or around how much  ::)

TheRock:
Lose 30 for an A, around 15 for an A* just in case.

ColdStorm:
Lose 30 Over All Or 30 In Paper 3 Only Thx By the way :)

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