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IG Chemistry Paper 3 discussion

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sweetie:

--- Quote from: bibo the wa7sh on June 02, 2009, 04:03:35 pm ---heY everYone,
wat about electrolysis of dilute sodium chloride???
Cathode..........
anode..............
and wat happens to the electrolyte???.....
WaiTinG 4 uR RepLies!!xD!!

--- End quote ---
at da cathode it was h2
at anode it was o2
so conc. NaCl was left

Shogun:
By the way to make an ester, u must write
carboxylic/ carboxylic gourp / or at least COOH    AND hydroxyl/hydorxyl group/alcohols or atleast Oh

^and waht notty_me said about the elctrolysis stuff is correct..

sweetie:
i got this tooooooo
but how do we no wats da valency of T?????????/

hdbkiwi:

--- Quote from: horror on June 02, 2009, 04:13:03 pm ---
--- Quote from: bibo the wa7sh on June 02, 2009, 04:03:35 pm ---heY everYone,
wat about electrolysis of dilute sodium chloride???
Cathode..........
anode..............
and wat happens to the electrolyte???.....
WaiTinG 4 uR RepLies!!xD!!

--- End quote ---
Cathode:sodium
anode chloride
electrolyte: used up
+rep me

--- End quote ---

nonono-the dilute sodium chloride means that you have more H+ and OH- in solution than Na+ and Cl-
soo
at the cathode, reduction occurs-in this DILUTE solution, hydrogen gas forms (half equation: 4H+(aq) + 4e-->2H2(g)
at the anode, OH- ions give up electrons, since not many Cl- ions are present. Oxygen bubbles off: 4OH- -->O2(g) +2H2O(l) +4e
When the hydrogen and oxygen bubble off, the Na+ and Cl- ions are left behind-so we still have a solution of sodium chloride!
The overall result is that water has been decomposed.

And for the Haber process question:
Air is nearly 80% nitrogen and 20% oxygen, with just small amounts of other gases. The oxygen is removed by burning hydrogen in the air.
2H2(g) + O2(g) -->2H2O (l)
That leaves mainly nitrogen.

Or you can say "the fractional distillation of liquid air"-another way to obtain nitrogen.

For Hydrogen:It is usually made from natural gas or methane, and water (as steam):
CH4(g) + 2H2O (g) -->(catalyst) CO2 (g) +4H2(g)
or you can crack compounds in oil (the alkanes)

Shogun:
see on the anode is oxygen on the (u cannot expect water to be stucked at the anode u know)
then hydrogen on the cathode as it is dilute and aqueous leveng chlorine and sodium, giving sodium chloride.

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