***2013 LC Chemistry Before/After***

mocker2012

lizardspock wrote: »

Yeah the sodium dichromate was the problem, carcinogenic or something I think. I'd love if ethanoic or ethanal came up though, theyre grand plus handy enough calculations. Don't actually know why I asked, just being nosy + looking for anything to distract me from accounting!:P

We just went ahead and did those experiments anyway!! YOLO:D

wow exuberant

My predictions: Ethanal or ethanoic acid (maybe both)
The rate of reactions expt with the hydrogen peroxide
iron Tablets titration

MarieCurie22

mocker2012 wrote: »

We just went ahead and did those experiments anyway!! YOLO:D

SHHH!The department of education can hear you!!!!

MarieCurie22

wow exuberant wrote: »

My predictions: Ethanal or ethanoic acid (maybe both)
The rate of reactions expt with the hydrogen peroxide
iron Tablets titration

Just because they came up on the DEB mock :P
Iron Tablets or BOD of water (BOD more likely)
Ethanl or Ethanoic acid
HCL and NaOH heat of rxn or affect of temp on rate of reaction...

MarieCurie22

there is no way in hell theyd ask both not a hope!

wow exuberant

MarieCurie22 wrote: »

there is no way in hell theyd ask both not a hope!

they've done it with ethyne and ethene before

wow exuberant

MarieCurie22 wrote: »

Just because they came up on the DEB mock :P
Iron Tablets or BOD of water (BOD more likely)
Ethanl or Ethanoic acid
HCL and NaOH heat of rxn or affect of temp on rate of reaction...

really lol? I honestly forgot what came up on our pre

MarieCurie22

wow exuberant wrote: »

really lol? I honestly forgot what came up on our pre

Iron tablets came up in 2009, BOD in 2003 i think? only once...so well over due...

lizardspock

mocker2012 wrote: »

We just went ahead and did those experiments anyway!! YOLO:D

whoah chem badass over here!!:pac:

simons545

MarieCurie22 wrote: »

Iron tablets came up in 2009, BOD in 2003 i think? only once...so well over due...

I agree, I think they're worth learning. They were on a mock if I'm not mistaken?
Anyone else have that woeful company examcraft correcting your mocks?
They marked 78% on my paper, forgot to add up two sections, didn't mark the answers even though given word for word and totaled near 60 odd marks missing.
and seriously, what's the deal with having no question numbers in chemistry and physics? You'd think all the "intellectuals" on the board...you can finish that.

MarieCurie22

simons545 wrote: »

I agree, I think they're worth learning. They were on a mock if I'm not mistaken?
Anyone else have that woeful company examcraft correcting your mocks?
They marked 78% on my paper, forgot to add up two sections, didn't mark the answers even though given word for word and totaled near 60 odd marks missing.
and seriously, what's the deal with having no question numbers in chemistry and physics? You'd think all the "intellectuals" on the board...you can finish that.

Tbf in chem they do label far better than physics so many times ive skipped questions cause of their inability to label their work! it also must be a nightmare correcting!

simons545

MarieCurie22 wrote: »

Tbf in chem they do label far better than physics so many times ive skipped questions cause of their inability to label their work! it also must be a nightmare correcting!

Yeah, I feel sorry for the poor examiners. I just put the first word of the question with some ":" after it and double check the questions. (They are colons right?) It just feels weird calling them colons after the biology exam on Friday...Tangent much. Back to the photoelectric effect... hf=...[/I
I envy the people with two days to study chemistry left...

MarieCurie22

simons545 wrote: »

Yeah, I feel sorry for the poor examiners. I just put the first word of the question with some ":" after it and double check the questions. (They are colons right?) It just feels weird calling them colons after the biology exam on Friday...Tangent much. Back to the photoelectric effect... hf=...[/I
I envy the people with two days to study chemistry left...

Not even that most of them had the whole weekend!

Hamza Malik

Just finished all my organic study How are people finding the mechanisms? Tbh I find them an easy 15+ marks

MarieCurie22

Hamza Malik wrote: »

Just finished all my organic study How are people finding the mechanisms? Tbh I find them an easy 15+ marks

Super bien although watch the wording of the questions sometimes they try trick you...so Hamza enlighten us all :P Cholorination of methane to form chloromethane?

SecondMan

SecondMan wrote: »

Woah 9%.. There's this guy in my class who comes out of every exam saying "That actually went very good. I'll be expecting at least a C". A week after, out come the results...F's all round. He lets on he's so intelligent. Just before the mocks he was finally persuaded by our Chem teacher to move to ordinary level after various replies back to her such as: "But I'm well able for a C in higher". Turn out he got 19% in ordinary level Chemistry in the mocks.

Well it's not that this guy thought it went well. He actually finds Chemistry very hard and had a good idea that he failed but he stayed in for 3 hours to try do his best. He stayed at Higher Level and we spent the last 5-6 weeks doing revision so he thinks he'll pass but it's a big step up!

Hamza Malik

MarieCurie22 wrote: »

Super bien although watch the wording of the questions sometimes they try trick you...so Hamza enlighten us all :P Cholorination of methane to form chloromethane?

Haha this will be good revision. So a CL2 molecule is broken in cl + cl by UV light.

Cl attacks methane to form Cl-h and methyl free radical.

The metyl free radical attacks another cl molecule. And causes a chain reaction..

Oh I forgot to mention it forms chloromethane.

Hamza Malik

Hamza Malik wrote: »

Just finished all my organic study How are people finding the mechanisms? Tbh I find them an easy 15+ marks

I think I'm the only person on boards who NEVER does q8/9 (depending on the year) because I can't understand the mechanisms at all! Or the different chromatographies. I'm hopeless at it! And then they ask for evidence to support it and I get more confused. Not a hope I'll be attempting it on Tuesday.

simons545

Deleted User wrote: »

Well it's not that this guy thought it went well. He actually finds Chemistry very hard and had a good idea that he failed but he stayed in for 3 hours to try do his best. He stayed at Higher Level and we spent the last 5-6 weeks doing revision so he thinks he'll pass but it's a big step up!

Fair play That was a very nice thing to do. Best of luck to him so and to everyone whooooo only 13 hours and 12 mins till physics ahahaha, fml...

simons545

Hamza Malik wrote: »

Haha this will be good revision. So a CL2 molecule is broken in cl + cl by UV light.

Cl attacks methane to form Cl-h and methyl free radical.

The metyl free radical attacks another cl molecule. And causes a chain reaction..

Oh I forgot to mention it forms chloromethane.

I think you should use reaction equations bud
You should throw in homolytic fission of Cl2 and the formation of the Carbonium ion. They will prob tie in something to do with bromine water/sodium chloride as well if they ask that tomorrow, so know the three products formed too! Oh and appropriate use of curly arrows!


Are these the three products formed with the Bromine water solution?
-1-chloro,2-bromoethane
-1-chloroethane (or dichloro?)
-2-bromoethanol

Tuesday I mean, getting ahead of myself...

MarieCurie22

Deleted User wrote: »

I think I'm the only person on boards who NEVER does q8/9 (depending on the year) because I can't understand the mechanisms at all! Or the different chromatographies. I'm hopeless at it! And then they ask for evidence to support it and I get more confused. Not a hope I'll be attempting it on Tuesday.

Hey I love teaching people stuff especially chemistry :P Ask Hamza....pretty decent too and would love to help you with the organic and mechanisms tomorrow evening?

woopah92

To whoever said the need to label the questions better, I agree 10000000%. I got 89% in the mock and I forgot to put in a definition that would have given me an extra 5 marks and 90% all because I didn't see that part of the question. My fault I know, I'm going to triple check all the questions on Tues. :pac:

mocker2012

simons545 wrote: »

I think you should use reaction equations bud
You should throw in homolytic fission of Cl2 and the formation of the Carbonium ion. They will prob tie in something to do with bromine water/sodium chloride as well if they ask that tomorrow, so know the three products formed too! Oh and appropriate use of curly arrows!


Are these the three products formed with the Bromine water solution?
-1-chloro,2-bromoethane
-1-chloroethane (or dichloro?)
-2-bromoethanol

Tuesday I mean, getting ahead of myself...

Thats evidence for ionic addition not substitution!!!:P

MarieCurie22

mocker2012 wrote: »

Thats evidence for ionic addition not substitution!!!:P

Evidence for substitution is...
-The formation of ethane (not present at start)
-The addition of tetramethyl lead speeds up rxn
-Only takes place in the presence of uv light!

outnumbered

MarieCurie22 wrote: »

Evidence for substitution is...
-The formation of ethane (not present at start)
-The addition of tetramethyl lead speeds up rxn
-Only takes place in the presence of uv light!

Check your Skype :P

Hamza Malik

simons545 wrote: »

I think you should use reaction equations bud
You should throw in homolytic fission of Cl2 and the formation of the Carbonium ion. They will prob tie in something to do with bromine water/sodium chloride as well if they ask that tomorrow, so know the three products formed too! Oh and appropriate use of curly arrows!


Are these the three products formed with the Bromine water solution?
-1-chloro,2-bromoethane
-1-chloroethane (or dichloro?)
-2-bromoethanol

Tuesday I mean, getting ahead of myself...

yeah I will. I didn't use them here cause its hard to type them.

And the products your talking about are from a different mechanism. Your talking about the bromination of ethene.

I'm talking about cholrination of methane

Hamza Malik

I hate chromatrography.. can I risk it to leave it out?

MarieCurie22

MarieCurie22 wrote: »

Hey I love teaching people stuff especially chemistry :P Ask Hamza....pretty decent too and would love to help you with the organic and mechanisms tomorrow evening?

Sure I don't mind if you're not too busy Just means I can keep my options open in the exam

weirdspider

simons545 wrote: »

I think you should use reaction equations bud
You should throw in homolytic fission of Cl2 and the formation of the Carbonium ion. They will prob tie in something to do with bromine water/sodium chloride as well if they ask that tomorrow, so know the three products formed too! Oh and appropriate use of curly arrows!


Are these the three products formed with the Bromine water solution?
-1-chloro,2-bromoethane
-1-chloroethane (or dichloro?)
-2-bromoethanol

Tuesday I mean, getting ahead of myself...

Its actually 1-bromo 2-chloroethane, I like to remember that they are in alphabetical order! And yeah its 1,2 dichloroethane

weirdspider

Hamza Malik wrote: »

I hate chromatrography.. can I risk it to leave it out?

Well paper chromatography isn't too bad! Just put a little dab on ink, put it in acetone and the different components seperate out. But I reckon you could, it only comes up as a tail of one of the choice Qs at the end. But just make sure you're not leaving too much stuff out already, that could be problematic on Tuesday! :P