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Author Topic: CHEMISTRY PAPER 1 HERE  (Read 38419 times)

Offline goin4dakill

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Re: CHEMISTRY PAPER 1 HERE
« Reply #285 on: June 11, 2009, 08:03:47 pm »
OK June 2005.

Which reacts with cold water only when finely powdered?
A. Calcium
B. Copper
C. Sodium
D. Magnesium

I put Sodium because its higher in the reactivity series, but the ms said magnesium...
WHY?? help urgently..?
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Offline sweetsh

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Re: CHEMISTRY PAPER 1 HERE
« Reply #286 on: June 11, 2009, 08:04:42 pm »
I think because Mg can be powdered ?
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Offline simba

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Re: CHEMISTRY PAPER 1 HERE
« Reply #287 on: June 11, 2009, 08:05:02 pm »
Quote from: VIP_93 on June 11, 2009, 07:59:20 pm
4 _ A ,cuz X is ionic so is solube in water and is the filterate while Y is organic so solube in organic solvents and is in the filterate too

15 _ A , cuz when 5g of X REACT WID 1000 cm , 500cm only react while the excess 500 are used to warm the mixture so when 500cm of water only react wid 5g then then all the 500cm react and there is no excess to warm the mixture and raise the temperature so the the decrease will be double

37 _ C cuz an acid will react with the carbonate to give bubbles of CO2
hope this helps
good luck ;) ;)

Thanks man
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Offline goin4dakill

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Re: CHEMISTRY PAPER 1 HERE
« Reply #288 on: June 11, 2009, 08:05:41 pm »
Quote from: sweetsh on June 11, 2009, 08:04:42 pm
I think because Mg can be powdered ?

Cant sodium be powdered????
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Offline VIP_93

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Re: CHEMISTRY PAPER 1 HERE
« Reply #289 on: June 11, 2009, 08:06:38 pm »
am not a man... am a girl ;) :D
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Offline sweetsh

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Re: CHEMISTRY PAPER 1 HERE
« Reply #290 on: June 11, 2009, 08:07:01 pm »
It can be cut by a knife but still not sure
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Offline simba

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Re: CHEMISTRY PAPER 1 HERE
« Reply #291 on: June 11, 2009, 08:09:25 pm »
srry girl anyways thanks
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Offline GodOfWar

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Re: CHEMISTRY PAPER 1 HERE
« Reply #292 on: June 11, 2009, 08:10:15 pm »
Quote from: simba on June 11, 2009, 07:50:27 pm
will someone help me in quetion 4 ,15, and 37 in nov.08

Q4 [A] --> well, its kinda hard to explain buh the main reason is becuz X being an ionic salt will dissolve (though all of them wont without heat) but Y wont being organic (like petrol), so u filter it out in 1,  and in 2 its the opposite cuz being organic Y HAS TO dissolve in ethanol.
Q15  ---> im not really sure miself, i chose B (its wrong; the rite answer is A) cuz the amount of reactant is decreasing, so they need less energy to form a product.
Q37 [C]--> thats one of the easiest really. Any Carbonate upon reacting with an acid will always produce CO2, so u get bubbles of gas.
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Offline VIP_93

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Re: CHEMISTRY PAPER 1 HERE
« Reply #293 on: June 11, 2009, 08:11:01 pm »
4 the june 2005 ques they want the metal that cant react wid cold water except wen finely powdered
so calcium can react even if its not powdered
and sodium th same thing
copper cant react
Mg reacts with steam and reacts SLOWLY wid water so wen we powder it it will react readily
gd luck ;)
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Offline astarmathsandphysics

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Re: CHEMISTRY PAPER 1 HERE
« Reply #294 on: June 11, 2009, 08:11:25 pm »
cjeck your email in 20 mins
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Offline Raed

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Re: CHEMISTRY PAPER 1 HERE
« Reply #295 on: June 11, 2009, 08:15:08 pm »
Quote from: john12345 on June 10, 2009, 02:13:25 pm
Quote from: esso on June 10, 2009, 01:26:02 pm
the answer is d cause chlorine is produced at the anode ,,, and because it bleaches the indicator the colour becomes white near the anode.....
and at the cathode the alkali is formed which turns indicator blue....

hope i helped,,,,....

Hey but what alkali is formed at the cathode
shouldnt hydrogen be formed at the cathode??








 hydrogen forms at cathod ..see all non matels except for hydrogen forms at anode and all metal icludin hydrogen forms a cathode! if it molten hydrogen is not at anode and in aq and in concetrated hydrogen is formed....



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Offline GodOfWar

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Re: CHEMISTRY PAPER 1 HERE
« Reply #296 on: June 11, 2009, 08:16:27 pm »
Quote from: goin4dakill on June 11, 2009, 08:03:47 pm
OK June 2005.

Which reacts with cold water only when finely powdered?
A. Calcium
B. Copper
C. Sodium
D. Magnesium

I put Sodium because its higher in the reactivity series, but the ms said magnesium...
WHY?? help urgently..?

Well. cuz Na is in the 1st group so it WILL react with cold water. Cu is very unreactive so obviously it wont. So u have Mg and Ca.
Ca like u said is more reactive, so it will react more readily while Mg will have to altered alittle to make it react.
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Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #297 on: June 11, 2009, 08:17:51 pm »
Quote from: GodOfWar on June 11, 2009, 08:16:27 pm
Quote from: goin4dakill on June 11, 2009, 08:03:47 pm
OK June 2005.

Which reacts with cold water only when finely powdered?
A. Calcium
B. Copper
C. Sodium
D. Magnesium

I put Sodium because its higher in the reactivity series, but the ms said magnesium...
WHY?? help urgently..?

Well. cuz Na is in the 1st group so it WILL react with cold water. Cu is very unreactive so obviously it wont. So u have Mg and Ca.
Ca like u said is more reactive, so it will react more readily while Mg will have to altered alittle to make it react.


mg is lower down the reactivity series so its most reactive
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Offline sweetsh

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Re: CHEMISTRY PAPER 1 HERE
« Reply #298 on: June 11, 2009, 08:18:41 pm »
No the highest at the rectivity series is the most reactive
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Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #299 on: June 11, 2009, 08:20:02 pm »
Quote from: sweetsh on June 11, 2009, 08:18:41 pm
No the highest at the rectivity series is the most reactive
yup sorry thts wat i meant
im just so stressed
thx for correcting
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