Qualification > Sciences
Chemistry Help HERE ONLY !!
Shogun:
--- Quote from: guru007 on May 30, 2009, 05:40:33 am ---
--- Quote from: Q80BOY on May 21, 2009, 06:22:57 pm ---hey guys,
as the chemsitry exam is on the 1st of june, u must all be revising, and u MUST have some questions,
so if u have any CHEMISTRY questions, post them here and hopefully some one will help.
Gd Luck :)
--- End quote ---
Hey Q80BOY
can u plz explain me extraction of aluminium ???
--- End quote ---
hey. extraction of aluminium works like this:
1)MOLTEN bauxite (aluminium oxide) is added to the vessel as an electrolyte.
2)sodium hydroxide is added to remove impurities like iron(II)oxides and sand.
3)since the boiling point of aluminium oxide is 2000oC, this will waste gr8 amount of energy. so to avoid this, cryolite is added to reduce its boiling point to 900oC.
4)then elctrolysis takes place, where aluminium becomes the cation and goes towards the cathode and settels at the bottom (as it is more dense) where it is extracted from.
5)the hot oxygen gas becomes an anion, rises towards the anode. Now the anode and cathode is made out f graphite(carbon), so the hot oxygen at the anode reacts with the carbon made anode to form carbon dioxide and eventually wear off. so then the anode shoul eventually be replaced.
well thts all, hope u understand, now they may ask u y carbon cannot be used to displace the oxygen from aluminium oxide to get aluminium. the answer,it wont happen, cuz carbon is more reactive than auminium(refer the reactivity series)
anything else u nedd just ask me ;D
X Abdulrahman X:
very nice explaination, + rep :]
Shogun:
Thanks, i made a mistake where i wrote tht aluminiuim settles at the bottom cuz it is "less dense" it should ve been "more dense" but dnt worry i modified it, (just to infrom)
zara:
im reallii confused in naming the alcohols...cn summon tll me plz.. ???
i need an explanation..
Thanks..
Tutu_93:
I have a dought in may june 2008 ( second variant) q 4 ii in balancing
I worked it out and i got this Li2O+ H2so4 = Li2SO4+ H2O
But in the marking scheme it is Li2O + H2SO4 Li2SO4 + 2H2O ?? can i knw y ??? ???
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