Author Topic: CHEMISTRY PAPER 1 HERE  (Read 38754 times)

Offline esso

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Re: CHEMISTRY PAPER 1 HERE
« Reply #30 on: June 10, 2009, 04:26:20 pm »
yah its core....just see the left hand column in the syllabus.....nd know abt dem...no need for the supplement things

nid404

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Re: CHEMISTRY PAPER 1 HERE
« Reply #31 on: June 10, 2009, 04:35:57 pm »
Let’s first consider the ions present
H+  OH-

Na+  Cl-



what exactly happens in the solution when electricity is passed through

The negative electrode(cathode) attracts the Hydrogen ions are attracted to it. They accept electrons to form hydrogen gas(which does not produce any change in the indicator)

At the positive electrode(anode), chloride ions are attracted. Here they lose two electrons to form chlorine gas. The chlorine bleaches the indicator.

The ions remaining form sodium hydroxide but the color change to blue is observed at the other electrode only because at the anode the indicator is bleached.


Ask again if u don't understand

oh allright got it thanx a lot nid. really nice of u to help

one more thing so de hydrogen formed at cathode doesnt affect de indicator becoz its as gas nd not as H+ ions,is dat de reason why de hydrogen gas has no effect on de indicator???

also so de sodium hydroxide is formed everywhere however it only affects the cathode region, because at the anode the litmus paper is bleached.. is dat rite
so if de litmus paper had not been bleached den even at de anode the litmus paper would have turned blue??

nd before chlroine turns damp blue litmus paper white it first turn the damn blue litmus paper red rite?? y is dat

nd one more question will sulphur dioxide gas react weith sodium hydroxide.. if yes what are the products

+ rep for u. Thanks a lot for ur help. hope im not wasting too much of ur time

which country r u from??

hydrogen gas simply does not affect the indicator. H+ions affect indiacators(since acids contain them)
if the indicator was not bleached it would have turned it blue throughout
It is in indicator in a solution(it's a universal indicator not litmus paper). *Chlorine does not turn litmus paper red anyways. The indicator is green in neutral solutions.

Sulphur dioxide will also react directly with bases such as sodium hydroxide solution. If sulphur dioxide is bubbled through sodium hydroxide solution, sodium sulphite solution is formed first followed by sodium hydrogensulphite solution when the sulphur dioxide is in excess. But y do u want to know this??



nid404

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Re: CHEMISTRY PAPER 1 HERE
« Reply #32 on: June 10, 2009, 04:37:13 pm »
and i forgot to mention.... I'm from India

....sorry for that robotic tone :D
« Last Edit: June 10, 2009, 04:40:03 pm by nid404 »

Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #33 on: June 10, 2009, 04:43:46 pm »
oh

thanx a lott

u seem to be a genius at chemistry
how do u know so much

u make me feel really dum :P

lol anywayz glad u know ur stuff really well

im from india as well

which city nd which school r u from??

guessing ur from bombay.. sound like dat


Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #34 on: June 10, 2009, 04:46:40 pm »
nd one more question

which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation

how do you solve this question

Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #35 on: June 10, 2009, 04:49:05 pm »
nd one more question lol sorry
i have quite sum questions

for which metal are de use nd property correctly linked
B aluminium for food containers as it is light and resistant to corrosion
or D satinless steel for cutlery as it is cheap and strong

A and C are wrong so its between B and D
which on'e correct nid??

Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #36 on: June 10, 2009, 04:50:21 pm »
Also
does anyone have the Chemisry Paper 1 for May and October 1993 since i cant seem to find dem anywhere

howcome dey are dere for physics nd biology but not for chem???

Offline Phosu

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Re: CHEMISTRY PAPER 1 HERE
« Reply #37 on: June 10, 2009, 05:09:54 pm »
nd one more question

which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation

how do you solve this question

its neutralisation

and the answer to the next question which i am to lazy to quote is, B its aluminium

Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #38 on: June 10, 2009, 05:11:41 pm »
nd one more question

which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation

how do you solve this question

de ,arkscheme says its oxidation

nd for de next question de markscheme says it steel???????

dats y i am confused

nd y is it neutralisation anywayz
its neutralisation

and the answer to the next question which i am to lazy to quote is, B its aluminium

nid404

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Re: CHEMISTRY PAPER 1 HERE
« Reply #39 on: June 10, 2009, 06:23:08 pm »
nd one more question

which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation

how do you solve this question

I find all of them except fermentation a possibility

Displacement- H2SO4+ 2 Na--> Na2SO4+H2
Neutralisation- NaOH+H2SO4-->Na2SO4+H2O
Oxidation- CH4+2O2-->CO2+2H2O

Can u post the paper it is from. i'll work on it and let u know...
and yup I'm from Bombay..MUMBAI

Offline IGCSE hater!

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Re: CHEMISTRY PAPER 1 HERE
« Reply #40 on: June 10, 2009, 08:51:20 pm »
can someone PLEASE help me...i need question papers for paper 1..i don't have any and i cant find them online either

Offline john12345

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Re: CHEMISTRY PAPER 1 HERE
« Reply #41 on: June 11, 2009, 04:10:54 am »
nd one more question

which process can convert molecules to a new substance by removing hydrogen atoms
A displacement
B fermentation
C neutralisation
D oxidation

how do you solve this question


hey i cant remeber de year it is from but this de exact question and according to the markscheme de answer is oxidation??

which school are u from in Mumbai??? ecole ?? podar?? ambani?? fazlani??
I find all of them except fermentation a possibility

Displacement- H2SO4+ 2 Na--> Na2SO4+H2
Neutralisation- NaOH+H2SO4-->Na2SO4+H2O
Oxidation- CH4+2O2-->CO2+2H2O

Can u post the paper it is from. i'll work on it and let u know...
and yup I'm from Bombay..MUMBAI

Offline shaxter8

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Re: CHEMISTRY PAPER 1 HERE
« Reply #42 on: June 11, 2009, 04:33:11 am »
GUYS, WHERE CAN I GET CHEMISTRY PAPER1 PAST PAPERS FROM 1993-2002?

Offline IGSTUDENT

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Re: CHEMISTRY PAPER 1 HERE
« Reply #43 on: June 11, 2009, 04:38:21 am »
Can someone pls help to get markschemes for chemistry paper 1 : may/nov 2001

Offline shaxter8

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Re: CHEMISTRY PAPER 1 HERE
« Reply #44 on: June 11, 2009, 05:28:25 am »
Can someone pls help to get markschemes for chemistry paper 1 : may/nov 2001
Hey IGSTUDENT, look at page 1 bottom of this topic, and you'll find the MS!