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Offline lonelyboy

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Chemistry Paper 1
« on: November 20, 2009, 07:14:10 am »
I just finished the paper. Phew. All exams done!

How was the paper? Hmmm. I'm not going to disobey the rules but all I can say is that it was slightly tricky. Alot of questions from the past papers were repeated though. Like not that far off past papers. So go through your past papers well, and learn your concepts well. It's slightly tricky. Lot of organic as usual. Along with Chemical bonds, Chemical equilibrium. xD
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Offline 123

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Re: Chemistry Paper 1
« Reply #1 on: November 20, 2009, 07:23:23 am »
Quote from: lonelyboy on November 20, 2009, 07:14:10 am
I just finished the paper. Phew. All exams done!

How was the paper? Hmmm. I'm not going to disobey the rules but all I can say is that it was slightly tricky. Alot of questions from the past papers were repeated though. Like not that far off past papers. So go through your past papers well, and learn your concepts well. It's slightly tricky. Lot of organic as usual. Along with Chemical bonds, Chemical equilibrium. xD
YEAH! finally i'm done with exams!! I don't think many questions were repeated....
MAybe cos i did 9701/12 !! Hmm...there must b 2 variants! which one did u do man???  It must be on ur statement of entry....lets not discuss it b4 24hrs!
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Offline lonelyboy

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Re: Chemistry Paper 1
« Reply #2 on: November 20, 2009, 07:27:20 am »
I did the 9701/12 mate. Same one. Well not alot lot, obviously but Chemistry does not repeat as much as Physics so it was a change to have atleast 5 questions which were sure shot exact. How was it for you? It's so hard to tell whether you'd end up scoring an A or not in Paper 1 because the margin is so less and also because you really have no idea if you're right or wrong. Like allowing for 3 definite mistakes, and rest on margin, I hope I should be able to scour above 30. With you mate?

Cheers.
 :)
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Offline 123

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Re: Chemistry Paper 1
« Reply #3 on: November 20, 2009, 07:44:24 am »
Oh i c! i thought there were 1-2 ques. repeated...damn i didn't recognise some repeats even though i did nearly all past papers=p
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Offline kratos009

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Re: Chemistry Paper 1
« Reply #4 on: November 20, 2009, 08:48:37 pm »
The paper was tricky. The paper was set out in a weird format, the easy questions were really easy, and the hard questions were extremely hard. there wasn't many questions that was in between. The organic questions were, i would say harder than those in the previous years but some of the questions you were able to answer pretty quickly. So overall the exam paper was ok, but some questions left my head feeling dizzy... :D.

Oh well i'm just glad that the exams are over ;D.
Have a GREAT holidays everyone!! ;D 
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Offline lonelyboy

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Re: Chemistry Paper 1
« Reply #5 on: November 21, 2009, 01:21:45 pm »
Yeah it was a bit weird actually.

I have a few doubts;

That question which said which of the following compounds have an Mr of 88,

Cyclohexane (?)
Primary OH/CHO
Secondary OH/CO

Was it all of them?

Then Limestone + water + ammonium sulphate would give:

sulfuric acid
calcium sulphate
ammonia

It was in the last 10 so which one could it be?

Then for that energy profile reaction which would give the highest yield and less time:

Was it A, B, C, D?

Then also for that propagation reaction, was it the one in which there was a free radical in both sides of the equation?
As if there are free radicals produced, then only the reaction will propagate?

For the function of Ag+ or Cu+ (don't remember), like in that sunglass equation,

what was the answer?
Ag is reducing
Ag is oxidising
Ag is catalyst
Stage 2 is where light is being absorbed?

Any other hard questions?

Where in Mani_DaDude By the way? He's noticeably absent mate.

Ohh one more, for that huge organic reaction, cis C20Hx or something which would form a cis-butene, what was the number of double bonds? 5 or 6?
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Offline MaNi_DaDuDe

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Re: Chemistry Paper 1
« Reply #6 on: November 21, 2009, 03:22:14 pm »
I've been out, sorry.

I'm posting this on my cellular. I'll reply to these and your pm when I get on my PC later tonight. :)

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Offline MaNi_DaDuDe

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Re: Chemistry Paper 1
« Reply #7 on: November 21, 2009, 10:12:06 pm »
Quote from: lonelyboy on November 21, 2009, 01:21:45 pm
Yeah it was a bit weird actually.

I have a few doubts;

My response to your queries are in bold and underlined. Thanks.

That question which said which of the following compounds have an Mr of 88,

Cyclohexane (?)
Primary OH/CHO
Secondary OH/CO

Was it all of them? I wrote all A - all of them :S

Then Limestone + water + ammonium sulphate would give:

sulfuric acid
calcium sulphate
ammonia

I wrote B? I wrote 2 and 3. No H2SO4 is produced

It was in the last 10 so which one could it be?

Then for that energy profile reaction which would give the highest yield and less time: I don't remember the question. Elaborate?

Was it A, B, C, D?

Then also for that propagation reaction, was it the one in which there was a free radical in both sides of the equation?
As if there are free radicals produced, then only the reaction will propagate? I chose C - The one with H as a radical. It was like + H- (the - was a circle lol)

For the function of Ag+ or Cu+ (don't remember), like in that sunglass equation,

what was the answer?
Ag is reducing
Ag is oxidising
Ag is catalyst That choice was Cu ions are catalysts
Stage 2 is where light is being absorbed?

I think D was the answer. I wrote C though (as A and B are wrongg)

Any other hard questions? The cis question's answer was the one with both Hydrogens being cis right? (not R1 and R2) - Most dipoles was B? Bond angels were A x,y,z ? Chiral Center was 3? #1 was D - h2 and br2 one was 2 and 2 - the 31 question about hydrogen bonds, etc was D? - Least # of carbon chains was  7? Oxidation was C or D ? I discussed most of these with a mate already; but just for re-assurance. . . :D

Where in Mani_DaDude By the way? He's noticeably absent mate. Just send me a pm when you need me to look at a particular topic.

Ohh one more, for that huge organic reaction, cis C20Hx or something which would form a cis-butene, what was the number of double bonds? 5 or 6? I don't remember. What were the options?

pz


-MaNi
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Offline kratos009

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Re: Chemistry Paper 1
« Reply #8 on: November 21, 2009, 10:16:28 pm »
Ummm, i'm not 100% sure about these answers but these what i put ;).

1. The M(88) i put C, only the last two because the first one comes out to 84 which does not equal 88, and i think i figured the last two out to equal 88.

2. For the limestone+ water + Ammonium sulphate, i put C again cause i don't think sulphuric acid is made from this reaction as i think the only way to make sulphuric acid is the Contact process or the reaction of Sulphur trioxide and water in the atmosphere to produce acid rain...

I don't know the answer to the other two/three questions you've posted, but i think for one of them one of the options in the answer was Cu and Cu2+ as a catalyst not Ag as a catalyst. I think i put the Cu and Cu2+ as a catalyst because all the other options didn't make sense :D.

3. oh yeah finally for that large organic molecule i was guessing between the 5 and 6 double bond, i think in the end i just put 6...

I'm just glad the exams are over ;D.
Enjoy your holidays and try not stressing too much about the exams. Just enjoy the holidays and the results would come when they come....
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Offline MaNi_DaDuDe

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Re: Chemistry Paper 1
« Reply #9 on: November 21, 2009, 11:11:46 pm »
Oh yeah! If the 88 question is the one with an aldehyde, a something and a ketone; the answer was both except ketone.
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Offline lonelyboy

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Re: Chemistry Paper 1
« Reply #10 on: November 22, 2009, 11:46:37 am »
Quote from: MaNi_DaDuDe on November 21, 2009, 10:12:06 pm
My response to your queries are in bold and underlined. Thanks.

That question which said which of the following compounds have an Mr of 88,

Cyclohexane (?)
Primary OH/CHO
Secondary OH/CO

Was it all of them? I wrote all A - all of them :S

Then Limestone + water + ammonium sulphate would give:

sulfuric acid
calcium sulphate
ammonia

I wrote B? I wrote 2 and 3. No H2SO4 is produced

It was in the last 10 so which one could it be?

Then for that energy profile reaction which would give the highest yield and less time: I don't remember the question. Elaborate?

Was it A, B, C, D?

Then also for that propagation reaction, was it the one in which there was a free radical in both sides of the equation?
As if there are free radicals produced, then only the reaction will propagate? I chose C - The one with H as a radical. It was like + H- (the - was a circle lol)

For the function of Ag+ or Cu+ (don't remember), like in that sunglass equation,

what was the answer?
Ag is reducing
Ag is oxidising
Ag is catalyst That choice was Cu ions are catalysts
Stage 2 is where light is being absorbed?

I think D was the answer. I wrote C though (as A and B are wrongg)

Any other hard questions? The cis question's answer was the one with both Hydrogens being cis right? (not R1 and R2) - Most dipoles was B? Bond angels were A x,y,z ? Chiral Center was 3? #1 was D - h2 and br2 one was 2 and 2 - the 31 question about hydrogen bonds, etc was D? - Least # of carbon chains was  7? Oxidation was C or D ? I discussed most of these with a mate already; but just for re-assurance. . . :D

Where in Mani_DaDude By the way? He's noticeably absent mate. Just send me a pm when you need me to look at a particular topic.

Ohh one more, for that huge organic reaction, cis C20Hx or something which would form a cis-butene, what was the number of double bonds? 5 or 6? I don't remember. What were the options?

pz


-MaNi


Hey MaNi,

Thanks mate. Well more or less, I got the same answers as you did. Made careless mistakes too but to be honest, more glad it's behind me. Paper 2 was alright and Paper 1 was not bad, so I'm hoping InshAllah for an A in this paper.

For that cyclo/aldehyde/ketone I do think it was all of them as the first one was I think
as the conditions were 4 carbon atoms

Butan-1,2-di-ol,
Ketone with a secondary alcohol so CH3COCH(OH)CH3 this would give 88
and Aldehyde with primary alcohol (or it was reversed) so CHOCH(OH)CH2CH3
And Butan-1,2-diol gives 88 as well.

Yeap I chose Ammonia + Calcium sulfate too. As limestone is used to neutralise acidity so I'm not sure where sulfuric acid comes into play with.

For that Cu2+ as catalysts, I did choose D myself (where light is being absorbed) as catalysts do not undergo reaction themselves and it seemed to be splitting into radicals it seems in the equation, but it was a wild guess ;)

Propagation I think I did choose the one you're talking about but can't exactly place it mate.Any other hard questions? The cis question's answer was the one with both Hydrogens being cis right? (not R1 and R2)  I don't remember but I was discussing this exact question, it had two parts, one was finding which was CIS and second was finding the number of double bonds or so,- Most dipoles was B? Most dipoles was I think the one with Chlorine or carbon as others were all symmetrical and C-H bond is hardly polarised. Bond angels were A x,y,z ? I've gotten an idea which one you're talking about but can't seem to place which one was A,x,y,z. The one which had 2 lone pair of electrons or if no 2 lone pairs, then one lone pair, one bond pair would have the smallest angle as the forces of repulsion are greater. Chiral Center was 3? Yeah, it was 3. I got it wrong, randomly chose 1 haha. #1 was D -[b]#1, which one was that..Oh! that number of, hmm I think it was 1800. Was there any answer like that or am I discussing some past paper? Ohh it was yeah! C4H8. I think D right mate.[/b]  h2 and br2 one was 2 and 2 - [b]Yeah got that too :P[/b] the 31 question about hydrogen bonds, etc was D? [b]It was B actually, 1,2, or C, 2,3 actually mate cus see hydrogen bond affects its melting/boiling point and the property of ice being denser than water because the hydrogen bonds arrange themselves tetrahedrally around carbon and in ice, this leads to less efficient packing of molecules hence less molecules per volume and so ice is denser. But hydrogen bond does not influence the bond angle of water. The lone pair of electrons (2) and the bond pairs of oxygen (2) do , resulting in approx. 104.5 degree angles.[/b] - Least # of carbon chains was  7? Yeah it was 7 mate. This question came in I think some 96 paper so yes, 7. Oxidation was C or D ? I got C actually mate but everybody else got D which means D is the right one.[/u][/b] I discussed most of these with a mate already; but just for re-assurance. . . :D

Hmm that maximum yield, less time had four energy profiles for a reaction (Reactants, products) and it showed the reaction path on the graphs for four of them. Which one would give maximum yield, in less time.

Thanks for your help though mate, means a lot.

Take care  ;)
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Offline lonelyboy

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Re: Chemistry Paper 1
« Reply #11 on: November 22, 2009, 11:51:50 am »
Quote from: kratos009 on November 21, 2009, 10:16:28 pm
Ummm, i'm not 100% sure about these answers but these what i put ;).

1. The M(88) i put C, only the last two because the first one comes out to 84 which does not equal 88, and i think i figured the last two out to equal 88.

2. For the limestone+ water + Ammonium sulphate, i put C again cause i don't think sulphuric acid is made from this reaction as i think the only way to make sulphuric acid is the Contact process or the reaction of Sulphur trioxide and water in the atmosphere to produce acid rain...

I don't know the answer to the other two/three questions you've posted, but i think for one of them one of the options in the answer was Cu and Cu2+ as a catalyst not Ag as a catalyst. I think i put the Cu and Cu2+ as a catalyst because all the other options didn't make sense :D.

3. oh yeah finally for that large organic molecule i was guessing between the 5 and 6 double bond, i think in the end i just put 6...

I'm just glad the exams are over ;D.
Enjoy your holidays and try not stressing too much about the exams. Just enjoy the holidays and the results would come when they come....

The last two were aldehyde, ketones...the first one was I think butan-1,2-diol. I think we had to find that out <- or something, not sure mate.

Yeah I put 6 as well only because it made more sense lol =P Random shot actually.

Haha yeah exams over mates, just let's forget about them and enjoy for a while haha. till jan 20th or something, Take care cheers hit me up if there's anything that needs to be discussed ;)
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Offline MaNi_DaDuDe

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Re: Chemistry Paper 1
« Reply #12 on: November 22, 2009, 05:02:57 pm »
No problem bro. = ]

Okay for that reactant product thing - I put the graph with the relatively smaller loop and I think I put the one where the products were on the bottom one and products were higher. :S

Yeah man InshaAllah, we'll all do great. Don't worry about it ;)

Take care
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Offline kratos009

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Re: Chemistry Paper 1
« Reply #13 on: November 22, 2009, 07:51:54 pm »
To be honest, the whole chem paper 1 seems like a blur now that 2 days of holiday has passed. So even if i do discuss the paper i probably won't be able to say an answer :D.
Well mostly i've put the same answers as you guys  ;D.
So...Enjoy your holidays. ;D
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