Author Topic: CHEMISTRY PAPER 1 HERE  (Read 38713 times)

Offline aquarian93

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Re: CHEMISTRY PAPER 1 HERE
« Reply #330 on: June 12, 2009, 01:56:15 am »
can anyone pls help me?

Offline Bani

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Re: CHEMISTRY PAPER 1 HERE
« Reply #331 on: June 12, 2009, 02:06:17 am »
can anyone pls help me?

I don't think you need to know the solubility of salts in acids and which salts react with acids....
Im not sure...

Offline Bani

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Re: CHEMISTRY PAPER 1 HERE
« Reply #332 on: June 12, 2009, 02:08:01 am »
Do hydrocarbons and polymers occur naturally?   i saw this Q in one of the past papers...
plzz helpp

Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #333 on: June 12, 2009, 02:27:51 am »
Do hydrocarbons and polymers occur naturally?   i saw this Q in one of the past papers...
plzz helpp

im guessing hydrocarbons do
but polymers
well actually some occur natural so yes

Offline amy.mym

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Re: CHEMISTRY PAPER 1 HERE
« Reply #334 on: June 12, 2009, 02:28:47 am »
Well their originality is from Dead animals and plants ?


Can anyone help me with Question 29 Paper 1 June 2004

how do we know the volume of Oxygen !


Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #335 on: June 12, 2009, 02:35:47 am »
Well their originality is from Dead animals and plants ?


Can anyone help me with Question 29 Paper 1 June 2004

how do we know the volume of Oxygen !



the volume of oxygen is 30cm3
but the air i have no idea
i think its bcuz thts the maximum mark on the gas syringe

Offline amy.mym

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Re: CHEMISTRY PAPER 1 HERE
« Reply #336 on: June 12, 2009, 02:37:32 am »
oh Thanks man

O.k  one more and thats it lol

emm how about the same paper ( June 2004 ) paper 1 Question 19 ?

Why is the answer ammonia ?

Offline Bani

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Re: CHEMISTRY PAPER 1 HERE
« Reply #337 on: June 12, 2009, 02:43:13 am »
Well their originality is from Dead animals and plants ?


Can anyone help me with Question 29 Paper 1 June 2004

how do we know the volume of Oxygen !



the volume of oxygen is 30cm3
but the air i have no idea
i think its bcuz thts the maximum mark on the gas syringe

its because oxygen is 21% of air,
so....just work out of the options available which would give the correct answer....

Offline amy.mym

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Re: CHEMISTRY PAPER 1 HERE
« Reply #338 on: June 12, 2009, 02:47:59 am »
REP + Thanks Bani

Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #339 on: June 12, 2009, 02:49:31 am »
oh Thanks man

O.k  one more and thats it lol

emm how about the same paper ( June 2004 ) paper 1 Question 19 ?

Why is the answer ammonia ?

bcuz al does not disslove in excess and zinc does so u can distinguish between them
for sodium hydroxide
both dissolve in excess so u cant tell the difference
gettit/?

Offline amy.mym

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Re: CHEMISTRY PAPER 1 HERE
« Reply #340 on: June 12, 2009, 02:58:50 am »
Ohhhhh yeah yeah thats the thing about the cations ans anions sheet that we had to learn

Thanks man appreciated


REP+ for u  :D

Offline amy.mym

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Re: CHEMISTRY PAPER 1 HERE
« Reply #341 on: June 12, 2009, 03:03:11 am »
hey sorry a few questions as well


In Nov 2000 Question 23

Why is it B ?



And June 2003 Question 16

No idea why its C

But is it because Copper II when in solution is blue ?

Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #342 on: June 12, 2009, 03:11:29 am »
hey sorry a few questions as well


In Nov 2000 Question 23

Why is it B ?



And June 2003 Question 16

No idea why its C

But is it because Copper II when in solution is blue ?

what has colour to do with it?
i really dont know why they use co2 instead of co sorry
i dont have nov 2000 dunno the question sorry bout tht too

thx amy + rep 2 u 2 ;D

Offline angell

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Re: CHEMISTRY PAPER 1 HERE
« Reply #343 on: June 12, 2009, 03:24:30 am »
Nov 2000

B because in a displacement reaction, a more reactive element displaces the less reactive one, therefore, CHLORINE is more reactive than BROMINE, and displaces it, hence BR2 is formed, which turns the solution brown!

Read up displacement reactions in ''The Periodic Table''

and for m/j 03

it is white to blue because it is 'hydrated'. it i s a copper sulphate salt, reversible reaction, when u add water it goes from white to blue. when u heat it, water is taken away, so blue to white!
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Offline kam

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Re: CHEMISTRY PAPER 1 HERE
« Reply #344 on: June 12, 2009, 03:34:56 am »
sorry amy i had the wrong paper
yes it is at first hydrated(with water) then dehydrates
notice they r asking about the products not reactants
 white toblue cuz when heated it turns white
then if u add water it turns blue
heat energy is taken out bcuz when u turn hydrated copper 2 sulphate its exothermic
but when opposite its endo

@angelll, u r right too
i just  wnted to explain the energy part as well