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Author Topic: CHEMISTRY PAPER 1 HERE  (Read 38708 times)

Offline Priceless

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Re: CHEMISTRY PAPER 1 HERE
« Reply #60 on: June 11, 2009, 10:34:02 am »
ok itz defi sodium 4 da 1st

but guyz 4 da 2nd...itz 'b'.....itz using copper electrodes wich r active electrodes.......im sure u hv don't da purification of copper using electrolysis...itz da same thng

n 3rd.....im not sure but i thnk itz sodium bcuz itz an alkali wich forms white compounds....

plz nid or any1...correct me if im wrong.....thnku :)
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Offline MR.BooMBastiC

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Re: CHEMISTRY PAPER 1 HERE
« Reply #61 on: June 11, 2009, 10:38:40 am »
Quote from: Priceless on June 11, 2009, 10:34:02 am
ok itz defi sodium 4 da 1st

but guyz 4 da 2nd...itz 'b'.....itz using copper electrodes wich r active electrodes.......im sure u hv don't da purification of copper using electrolysis...itz da same thng

n 3rd.....im not sure but i thnk itz sodium bcuz itz an alkali wich forms white compounds....

plz nid or any1...correct me if im wrong.....thnku :)


yeah....priceless

thats wat i said...2 is b
cuz cu electrodes r being used!!!!
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Re: CHEMISTRY PAPER 1 HERE
« Reply #62 on: June 11, 2009, 10:39:12 am »
 
Quote from: cockyxrocker on June 11, 2009, 10:16:23 am
OK so I have a few questions

1)hydrogen can form both ionic and covalent compounds
with which element will hydorgen form an ionic compound?
a-carbon
b-chlorine
c-nitrogen
d-sodium

2)CuSO4 (aq) is electrolysed using Cu electrodes
what observations will be made?

           at anode               at cathode               electrolyte
a-        anode dissolves      pink solid forms        blue color fades
b-        anode dissolves      pink solid forms        no change
c-      colourless gas forms  colourless gas forms  no change
d-     colourless gas forms  pink solid forms         blue color fades

3)  The carbonate of metal x is a white solid
it decomposes  when heated to form co2 gas and a yellow solid oxide
what is metal x

a-copper
b-iron
c-lead
d-sodium

Can somebody please answer them with explaination
Thanks
Last one has to be iron.
Copper oxide is black.
Sodium carbonate doesn't decompose.
Iron oxide is yellow.
Lead oxide is dark brown-black
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Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #63 on: June 11, 2009, 10:40:11 am »
Quote from: Priceless on June 11, 2009, 10:34:02 am
ok itz defi sodium 4 da 1st

but guyz 4 da 2nd...itz 'b'.....itz using copper electrodes wich r active electrodes.......im sure u hv don't da purification of copper using electrolysis...itz da same thng

n 3rd.....im not sure but i thnk itz sodium bcuz itz an alkali wich forms white compounds....

plz nid or any1...correct me if im wrong.....thnku :)
IT CANT BE B for da second one because the overall concentration of cu2+ ions remain the saME its jus the copper frm the anode tht gets coated on the cathode
n abt 3 it culd be copper

it cannot be sodium because carbonates of highly reactive metals are quite stable n do not  decompose on heating except lithium i think n copper oxide i think is yellow sort of

plz correct me if im wrong
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Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #64 on: June 11, 2009, 10:41:04 am »
yea srry copper oxide is black
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Offline MR.BooMBastiC

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Re: CHEMISTRY PAPER 1 HERE
« Reply #65 on: June 11, 2009, 10:42:34 am »
Quote from: madee on June 11, 2009, 10:41:04 am
yea srry copper oxide is black

yep..but da 3rd one i doubt da question.....none can be yellow....

By the way....he is not replying......wrs he...cocky..
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Re: CHEMISTRY PAPER 1 HERE
« Reply #66 on: June 11, 2009, 10:44:00 am »
Quote from: MR.BooMBastiC on June 11, 2009, 10:42:34 am
Quote from: madee on June 11, 2009, 10:41:04 am
yea srry copper oxide is black

yep..but da 3rd one i doubt da question.....none can be yellow....

By the way....he is not replying......wrs he...cocky..

Umm, iron (III) oxide is yellow.
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Offline Priceless

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Re: CHEMISTRY PAPER 1 HERE
« Reply #67 on: June 11, 2009, 10:44:59 am »
xactly madee.....so dats y ders no change in da electrolyte....so it is 'b'...

n thnkz though madee n i-insane...i 4got abt dat sodium CO3 duznt decompose......but is iron carbonate white?
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Offline MR.BooMBastiC

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Re: CHEMISTRY PAPER 1 HERE
« Reply #68 on: June 11, 2009, 10:45:29 am »
no.its brown
i guess...........

i havent been to the lab since 2 years.. .......!!!!

my cheap school [sighs]
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Offline simba

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Re: CHEMISTRY PAPER 1 HERE
« Reply #69 on: June 11, 2009, 10:46:57 am »
hey guyz will somebody help me in this question number 25 november 06.....
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Offline Priceless

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Re: CHEMISTRY PAPER 1 HERE
« Reply #70 on: June 11, 2009, 10:49:37 am »
Quote from: MR.BooMBastiC on June 11, 2009, 10:45:29 am
no.its brown
i guess...........

i havent been to the lab since 2 years.. .......!!!!

my cheap school [sighs]

lol...cmon mr bombastic..... :)

but nw im evn more confused.....wats da answer den ???......wers cockyx?
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Re: CHEMISTRY PAPER 1 HERE
« Reply #71 on: June 11, 2009, 10:50:56 am »
Quote from: Priceless on June 11, 2009, 10:44:59 am
xactly madee.....so dats y ders no change in da electrolyte....so it is 'b'...

n thnkz though madee n i-insane...i 4got abt dat sodium CO3 duznt decompose......but is iron carbonate white?


No kidding, but I've never even heard of zinc carbonate :P
But, sodium carbonate doesn't decomposes, lead oxide is black, copper oxide is black, iron oxide is yellow..so iron is the only thing possible. Even if you consider sodium, sodium oxide is white.
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Offline shafiq_92libra

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Re: CHEMISTRY PAPER 1 HERE
« Reply #72 on: June 11, 2009, 10:51:42 am »
Quote from: sweetest angel on June 11, 2009, 10:25:35 am
1) SODIUM SINCE ITS DA ONLY METAL
2) "D" SINCE hydroxide is colourless gas...copper pink solid!!
3)can u post the paper...i remeba doin' it buh cnt give xact explanation unless sure of answer!

you ppl sure
i think it shud b chlorine cos hcl is an ionic compound in liquid
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Offline Priceless

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Re: CHEMISTRY PAPER 1 HERE
« Reply #73 on: June 11, 2009, 10:54:50 am »
yes shafiq...im pretty sure abt sodium.....ionic compounds is da bonding b/w a metal n a non-metal....

n i-insane.....lol....i guess itz iron den but not sure though......thnkz though...all da best :)
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Offline shafiq_92libra

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Re: CHEMISTRY PAPER 1 HERE
« Reply #74 on: June 11, 2009, 10:55:31 am »
yah but nah sounds wrong 0_0
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