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Author Topic: CHEMISTRY PAPER 1 HERE  (Read 38445 times)

Offline sweetest angel

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Re: CHEMISTRY PAPER 1 HERE
« Reply #105 on: June 11, 2009, 12:32:47 pm »
Quote from: esso on June 11, 2009, 12:23:13 pm
i need help in this question <

 Three reactions used in the manufacture of sulphuric acid are shown.
1 S + O2 ? SO2
2 2SO2 + O2 ? 2SO3
3 SO3 + H2O ? H2SO4
Which of these reactions are redox reactions?
A 1 only
B 3 only
C 1 and 2 only
D 2 and 3 only
2 and 3?
i saw this question be4...can u tell me which year please?
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Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #106 on: June 11, 2009, 12:33:32 pm »
Quote from: Clem on June 11, 2009, 12:26:30 pm
Hey! Can someone tell me why q4 in november 08 is A? Ionic compounds are soluble in ethanol and water
And also november 2007 no. 21, shouldn' it form a blue percepitate??


ionic compounds dissolve in water n covalent dont n covalent dissolve in organic solvents n ionic dont so with either methods dey can be separated the undissolved compound is left as reidue
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Offline winnie101

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Re: CHEMISTRY PAPER 1 HERE
« Reply #107 on: June 11, 2009, 12:35:48 pm »
the ans is actually c, 1and2
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Offline mizuki

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Re: CHEMISTRY PAPER 1 HERE
« Reply #108 on: June 11, 2009, 12:36:00 pm »
hey when you polymerise an an alkene,e.g. ethene,does it become polyethEne or polyethAne?
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Offline Triple_A

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Re: CHEMISTRY PAPER 1 HERE
« Reply #109 on: June 11, 2009, 12:37:31 pm »
Quote from: madee on June 11, 2009, 12:33:32 pm
Quote from: Clem on June 11, 2009, 12:26:30 pm
Hey! Can someone tell me why q4 in november 08 is A? Ionic compounds are soluble in ethanol and water
And also november 2007 no. 21, shouldn' it form a blue percepitate??


ionic compounds dissolve in water n covalent dont n covalent dissolve in organic solvents n ionic dont so with either methods dey can be separated the undissolved compound is left as reidue
reagent aq BaCl is wrong
@mizuki........polyethene
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Offline sweetie

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Re: CHEMISTRY PAPER 1 HERE
« Reply #110 on: June 11, 2009, 12:41:00 pm »
oct05 que.32
may06 que.19
oct06 que.5

can any1 plzzzzzz xplain ans. 2 dese que"s
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Offline winnie101

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Re: CHEMISTRY PAPER 1 HERE
« Reply #111 on: June 11, 2009, 12:44:02 pm »
hi
does anyi know why the ans to q29, 2004jun is C
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Offline cool_dude

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Re: CHEMISTRY PAPER 1 HERE
« Reply #112 on: June 11, 2009, 12:53:57 pm »
u guys..
help me..

ppr 1,june04, 32..
why would the screws be the aluminium?..
aluminium would never corrode..because it forms oxide layer?
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Offline esso

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Re: CHEMISTRY PAPER 1 HERE
« Reply #113 on: June 11, 2009, 12:54:38 pm »
Quote from: sweetest angel on June 11, 2009, 12:32:47 pm
Quote from: esso on June 11, 2009, 12:23:13 pm
i need help in this question <

 Three reactions used in the manufacture of sulphuric acid are shown.
1 S + O2 ? SO2
2 2SO2 + O2 ? 2SO3
3 SO3 + H2O ? H2SO4
Which of these reactions are redox reactions?
A 1 only
B 3 only
C 1 and 2 only
D 2 and 3 only
2 and 3?
i saw this question be4...can u tell me which year please?

its in may june 2007 .... but can u explain it ????
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Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #114 on: June 11, 2009, 12:58:37 pm »
Quote from: notty_me on June 11, 2009, 12:41:00 pm
oct05 que.32
may06 que.19
oct06 que.5

can any1 plzzzzzz xplain ans. 2 dese que"s
for the first one its lime bcoz lime is calciumcarbonate bcoz it consists of calcium which is highly reactive n will not decompose

for the second metals below hydrogen will not react with acids n copper is below hydrogen all the others will react
n for the last one its C
the 35 n 37 are isotopes of chlorine n the 18 is argon chk the periodic table
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some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #115 on: June 11, 2009, 01:03:58 pm »
Quote from: winnie101 on June 11, 2009, 12:44:02 pm
hi
does anyi know why the ans to q29, 2004jun is C
take the percentage of o2 to be 21% now
21/100*x=30
solve u will get 142 sumthin so the nearest value is 150 so it is c
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some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline Clem

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Re: CHEMISTRY PAPER 1 HERE
« Reply #116 on: June 11, 2009, 01:04:35 pm »
Quote from: Triple_A on June 11, 2009, 12:37:31 pm
Quote from: madee on June 11, 2009, 12:33:32 pm
Quote from: Clem on June 11, 2009, 12:26:30 pm
Hey! Can someone tell me why q4 in november 08 is A? Ionic compounds are soluble in ethanol and water
And also november 2007 no. 21, shouldn' it form a blue percepitate??


ionic compounds dissolve in water n covalent dont n covalent dissolve in organic solvents n ionic dont so with either methods dey can be separated the undissolved compound is left as reidue
reagent aq BaCl is wrong
@mizuki........polyethene

Thanks! XD

Why is it wrong? It will form a blue percepitate of copper chloride right?
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Offline 247sports

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Re: CHEMISTRY PAPER 1 HERE
« Reply #117 on: June 11, 2009, 01:06:00 pm »
Quote from: sweetest angel on June 11, 2009, 12:32:47 pm
Quote from: esso on June 11, 2009, 12:23:13 pm
i need help in this question <

 Three reactions used in the manufacture of sulphuric acid are shown.
1 S + O2 ? SO2
2 2SO2 + O2 ? 2SO3
3 SO3 + H2O ? H2SO4
Which of these reactions are redox reactions?
A 1 only
B 3 only
C 1 and 2 only
D 2 and 3 only
2 and 3?
i saw this question be4...can u tell me which year please?

may/june 2007  :)
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Offline girl_92

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Re: CHEMISTRY PAPER 1 HERE
« Reply #118 on: June 11, 2009, 01:07:49 pm »
Quote from: cool_dude on June 11, 2009, 12:53:57 pm
u guys..
help me..

ppr 1,june04, 32..
why would the screws be the aluminium?..
aluminium would never corrode..because it forms oxide layer?
here dey r testing for preferential discharge thing aluminium is more reactive hence it will loose electrons n will not let steel to do so
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some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline cool_dude

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Re: CHEMISTRY PAPER 1 HERE
« Reply #119 on: June 11, 2009, 01:14:08 pm »
Quote from: madee on June 11, 2009, 01:07:49 pm
Quote from: cool_dude on June 11, 2009, 12:53:57 pm
u guys..
help me..

ppr 1,june04, 32..
why would the screws be the aluminium?..
aluminium would never corrode..because it forms oxide layer?
here dey r testing for preferential discharge thing aluminium is more reactive hence it will loose electrons n will not let steel to do so

oh...really?..
i alwys keep rembr that aluminium doesn't corrode..
nways..thanks..+rep
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