Author Topic: IG Chemistry Paper 3 discussion  (Read 24290 times)

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #135 on: June 02, 2009, 12:37:40 pm »
i think so u guys got sum other variant...

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #136 on: June 02, 2009, 12:38:18 pm »
atuallt i dont realli remember the ppr...the ques i mean..

Offline sweetie

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Re: IG Chemistry Paper 3 discussion
« Reply #137 on: June 02, 2009, 12:40:16 pm »
oh, no zara i was askin bout wich groups?

so kim is it rong 2 say carboxyl & hydroxyl??

Offline Kim

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Re: IG Chemistry Paper 3 discussion
« Reply #138 on: June 02, 2009, 12:45:26 pm »
oh, no zara i was askin bout wich groups?

so kim is it rong 2 say carboxyl & hydroxyl??
]
nopt that i know of cause it means the same thing cause u just wrote more bigger terms
sp dont worry u got ur 2 marks or 1 mark or watver it was
After all is said and done, more is said than done.

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Offline LoCo93

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Re: IG Chemistry Paper 3 discussion
« Reply #139 on: June 02, 2009, 01:25:27 pm »
the two blanks abt the acrylic acid??
well the answer was lactic acid and water

urgh thank god umm not the onli one who rote that.. <3..

By the way what did u guys ryte for the question abt making sure its an acid.. ??
Urgh.. Bored.. !! help!!! =[

Offline LoCo93

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Re: IG Chemistry Paper 3 discussion
« Reply #140 on: June 02, 2009, 01:31:00 pm »
for the bond energies they were H----H and F----F and 2H----F
we add the bond energies for H----H and F----F
then we multiply 2 by H----F
then we subtract (H----H + F----F)- (2*H---F)
the ans will be negative


wohoo i did the same thng.. got a -530 :S.. or sumthn..
Urgh.. Bored.. !! help!!! =[

zara

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Re: IG Chemistry Paper 3 discussion
« Reply #141 on: June 02, 2009, 01:38:36 pm »
the two blanks abt the acrylic acid??
well the answer was lactic acid and water

urgh thank god umm not the onli one who rote that.. <3..

By the way what did u guys ryte for the question abt making sure its an acid.. ??
i rote react it with a base.....salt and water will form....though im nt sure if its rite or rong...

Offline LoCo93

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Re: IG Chemistry Paper 3 discussion
« Reply #142 on: June 02, 2009, 01:42:54 pm »
i rote sumthin like add a magneisum (or any metal) ribbon and if its acidic it'll react..  ??? ??? ::) dont kno tho..
Urgh.. Bored.. !! help!!! =[

Offline LoCo93

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #143 on: June 02, 2009, 01:45:07 pm »
i rote silicon was the limitin reagent but ppl keep sayin it was fluorin..

i rote silicon cus it was in shotest supply :S..
Urgh.. Bored.. !! help!!! =[

Offline Ukhti-R

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #144 on: June 02, 2009, 02:06:05 pm »
yeah loco.. I rote silion too... itt had the least amount of moles...
"...And whosoever fears Allah and keeps his duty to Him, He will make a a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allah, then He will suffice him." [65: 2-3]

Offline posten

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Re: SaFe To DiScUsS ChEm NoW!!!!
« Reply #145 on: June 02, 2009, 02:32:45 pm »
Quote
what was the answer for chorophyll?
-do chromatography for the cholorophyll sample and compare the results with the one drawn above it will give one spot matching with the same height in both.

Offline thukon

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Re: IG Chemistry Paper 3 discussion
« Reply #146 on: June 02, 2009, 02:33:44 pm »
i rote sumthin like add a magneisum (or any metal) ribbon and if its acidic it'll react..  ??? ??? ::) dont kno tho..
But GUYS.... the question asked how you could determine the compounds contained the same COOH group!! Just because it reacts with a base or a carbonate wont tell that its a COOH group.

Offline aquarian93

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Re: IG Chemistry Paper 3 discussion
« Reply #147 on: June 02, 2009, 02:42:18 pm »
u guys, i drew a chormatography diagram for the first, its okay rite?
for the energy thing i got -530
for the adv of PLA i rote, its non biodegradable and wont pollute the environment wen burnt with harmful gases (CO2) :S
the source for nitrogen, i said nitrogen fixation bacteria :(
i said we wash the precipitate to remove impurities
and put it in the oven to get it in molten state if needed

cn anyone pls verify my answers..?

the question after the limiting agent one, was how much of mass of SiF was collected rite? i forgot
by the look of it, i think i lost 10-15 marks :(
does anyone, by any chance noe if that cn still be an A/A*

i thoght the paper was too long, we usually get 7 questions. and it was a whole lotta math/bio, weird.

Offline bibo the wa7sh

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Re: IG Chemistry Paper 3 discussion
« Reply #148 on: June 02, 2009, 03:25:11 pm »
heY everYone,
wat about electrolysis of dilute sodium chloride???
Cathode..........
anode..............
and wat happens to the electrolyte???.....
WaiTinG 4 uR RepLies!!xD!! :o

Offline ETCH

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Re: IG Chemistry Paper 3 discussion
« Reply #149 on: June 02, 2009, 03:28:01 pm »
at the cathode hydrogen is produced, at the anode oxygen is produced and the electrlyte becomes more concentrated.