Chemistry build up and aftermath

smndly

Does anyone know why HCl cannot be used to ensure acidic conditions for KMnO4?? Is it because it releases chlorine gas?

rainbowtrout

-JammyDodger- wrote: »

Just for clarification rainbowtrout, does that only apply to ordinary level? Could it be one of either for higher level?

Ya, that's Ordinary Level only. I think the Industrial and Environmental option is called 1A and 1B and the Electrochemistry/Molecules and Crystals one is called 2A and 2B (in the Chemistry syllabus).

In ordinary level you only need to study one option from Option 1 or one from Option 2 and they alternate which will be on the paper each year, one from each obviously, so as I said for the first option it will be Environmental this year and in the second option molecular structure was on last year's paper so it should be the Electrochemisty option this year.


In Higher Level when you are choosing an option you need to study both chapters eg 1 A and 1B and either one could come up. There is no pattern to it at HL either, the first three years of the new course 02 was Industrial and 03/04/05 was Environmental for the first option so when I had a class in 06 I took a gamble and just did Industrial for my 06 LC Class as it was due an appearance and it came up. Last two years it was Environmental again. I would expect Industrial is due an appearance this year.

I don't teach the other option so I can't comment on it, but if you have done it just flick back through the papers and have a look at the pattern.

rainbowtrout

smndly wrote: »

Does anyone know why HCl cannot be used to ensure acidic conditions for KMnO4?? Is it because it releases chlorine gas?

Yes correct but the technical answer (and they are quite technical with the chem marking scheme ) is that KMnO4 oxidises the chlorine ions (Cl-) to Cl2 gas. I don't remember the page :pac: but if you are working from Chemistry live its on the bottom right hand paragraph of Ch 15, Redox Reactions.

mikeglee

can anyone give some advice on wether to do ordinary or higher? Maybe point out the difference between both

rainbowtrout

mikeglee wrote: »

can anyone give some advice on wether to do ordinary or higher? Maybe point out the difference between both

I think first question there should be how have you been doing at HL over the past 2 years and do you need it for points/course requirement? How did you get on in the mocks?

mikeglee

rainbowtrout wrote: »

I think first question there should be how have you been doing at HL over the past 2 years and do you need it for points/course requirement? How did you get on in the mocks?

I have been doing higher for the last two years and its been a VERY rocky road. THE MOCKS = NOT GOOD

rainbowtrout

mikeglee wrote: »

I have been doing higher for the last two years and its been a VERY rocky road. THE MOCKS = NOT GOOD

What exactly is not good? >30%??? or more in the region of 15%.... Personally I would advise students getting below 30% to do OL in any subject (there are always exceptions of course).

Do you need it for points?

mikeglee

rainbowtrout wrote: »

What exactly is not good? >30%??? or more in the region of 15%.... Personally I would advise students getting below 30% to do OL in any subject (there are always exceptions of course).

Do you need it for points?

OK....i've made my decision!

rainbowtrout

mikeglee wrote: »

OK....i've made my decision!

I would just advise you to have a chat with your chemistry teacher during the week about your decision if you get the chance. Good luck


... and just as another point if you are doing OL, if you are working from Chemistry Live, anything with a red line margin is HL only

Chapters with a lot of OL information
Water
Rates of Reaction
Structure of Molecules/Periodic Table (ch 3,4,5)
Mole/Stoichiometry
Volumetric Analysis/Titrations... the only titrations on OL are acid/base ones, so make sure you know it.
Electrochemisty
Organic Chemistry - Ethene and Ethyne experiments come up nearly every year in some form or other, so make sure you know the chemicals used, the type of reaction it is and the tests for ethene/ethyne

Nimur90

I have 5 days between art history and chemistry so for the last few months I neglected it hoping that I can bring myself to study it loads over that few days.

smndly

Last year wen i did the leaving i got a D1 in physics in the mocks which is a similar subject to chemistry. I then got an A1 in the Leaving. So if you hav put in the effort since ur mocks theres no reason you shudnt do higher. That said you know better than anyone else!! If your confident that your not going to fail, go for it! :pac:

mikeglee

HELP!!!! I'm trying to study but it's not working. All I see is a book covered in highlighter pen. It defeats the purpose of even having a highlighter!

movingsheepdip

mikeglee wrote: »

It's my worst subject and I'm trying my best to come to terms with the fact that the time is nearly here. Has anyone got any thoughts or comments about how they are getting on with study and preperation?

haha you looked

splashdown for chemistry: 14:00 hours next tuesday

Thanks rainbowtrout.

Do you think it would be safe to leave out water? I'm good with everything on the course, really, but I just haven't covered water. My plan is to leave out pH and water, anyway. I'm not sure about the water titrations though, I suppose I'll have to cover them.

rainbowtrout

-JammyDodger- wrote: »

Thanks rainbowtrout.

Do you think it would be safe to leave out water? I'm good with everything on the course, really, but I just haven't covered water. My plan is to leave out pH and water, anyway. I'm not sure about the water titrations though, I suppose I'll have to cover them.

Well if you know everything else on the course, it wouldn't be the end of the world to leave it out, you would still have a good choice.

It would be a good idea to do the titrations, they haven't asked one since 2005. It also came up in 2004. Last year there was 1 and half questions on water in section B of the paper so I would imagine there won't be as much this year.

Q8: Ionic product and pH, water treatment
Q10: Suspended and dissolved solids, test for chlorine


That pretty much covered all of water theory so I can't see there being as much on this year. But I wouldn't rule out a titration.

Frolick

Come on Iron Table exp. and Production of ethyne exp.!
They came up that would be sweet and i think there due

fabgooner

smndly wrote: »

Does anyone know why HCl cannot be used to ensure acidic conditions for KMnO4?? Is it because it releases chlorine gas?

probably gets involved in the titration?

fabgooner

juat make sure you revise all the organic and water. guaranteed questions:D

mikeglee

fabgooner wrote: »

juat make sure you revise all the organic and water. guaranteed questions:D

what are the main differences between higher and ordinary?

Polarity

Ok, so Chromatography, Steam Distillation, Hydrogen Peroxide and Vinegar all came up in Section A last year. Does this mean it's safe to leave them out of my study??

I want to be able to do all 3 Q's in that section, so I'm planning to do all the other experiments.

Thanks and good luck!

whadabouchasir

Polarity wrote: »

. Does this mean it's safe to leave them out of my study??

Not if the chemistry examiners think like the Irish ones do.

mikeglee

4 days till D-Day folks

DDC1990

Our teacher said Ethene and Ethyne might come up as one q as Q1
For Q 2 she said possibly Iron Tablets or Vineger Titration.
Q3, she said anything could come up, but Rates of Reaction and Stuff would be top of the pile.



Having said all that she is a rubbish teacher, and gets the definitions backwards... a lot!

mikeglee

DDC1990 wrote: »

Our teacher said Ethene and Ethyne might come up as one q as Q1
For Q 2 she said possibly Iron Tablets or Vineger Titration.
Q3, she said anything could come up, but Rates of Reaction and Stuff would be top of the pile.



Having said all that she is a rubbish teacher, and gets the definitions backwards... a lot!

Are we in the same class or something?:D:D:D:D:D

smndly

DDC1990 wrote: »

Our teacher said Ethene and Ethyne might come up as one q as Q1
For Q 2 she said possibly Iron Tablets or Vineger Titration.
Q3, she said anything could come up, but Rates of Reaction and Stuff would be top of the pile.



Having said all that she is a rubbish teacher, and gets the definitions backwards... a lot!

Well Q1 is the titration and Q2 is the organic and emm vinegar AND ethene came up last year so there not gonna come up this year.

bstoran

volatile liquid and bleach look v.likely....hope le chateliers, redox reactions and anions dont come up...

OxfordComma

Anyone else really HATE electrolysis? It wrecks my head. Thank god it's such a small part of the course.

Chemistry's grown on me a lot over the past two years actually...

QueenOfLeon

smndly wrote: »

Well Q1 is the titration and Q2 is the organic and emm vinegar AND ethene came up last year so there not gonna come up this year.

Ethene came up 3 years in a row, once in section A and twice in section B, i wouldn't leave it out!

not bakunin

ok.........so, how many questions can i nail without going near maths in the paper? any ideas...........im diabolical with numbers, ive a close and figure devoid mind.

i acknowledge that i will have to admit defeat and get out the old calculator and become puzzled-face boy with-lots-of-scribbles-on-his-answerbook-and-a-stupid-answer-with-made-up-maths, but how far can i get before reaching that point?

that, my edelweisses, is the question.

MissRealist

smndly wrote: »

Does anyone know why HCl cannot be used to ensure acidic conditions for KMnO4?? Is it because it releases chlorine gas?

Oh oh oh! I think I actually know this one!:eek:. Cl is an oxidising agent and messes with the rxn.