!! LC Chemistry '16 HL - Before and after ...

lc16_

Hey guys, I was just wondering would it be safe to leave out the experiments that were asked in last years paper, same goes for the Q5 (Bohr&Rutherford exp) ?

Thanks!

Corkalex

Gonna skim over the stuff that came up last year but wouldn't skip it

Bangdiggy

lc16_ wrote: »

Hey guys, I was just wondering would it be safe to leave out the experiments that were asked in last years paper, same goes for the Q5 (Bohr&Rutherford exp) ?

Thanks!

Since it's a new examiner she might decide to put up something from last year(maybe, you never know) so I'd say know it

TMJM96

Not a LC Chem student but...

Don't "skip" topics that showed up last year, skim over it as a minimum. The SEC like repeating topics, especially if it was answered poorly the previous year.

Bangdiggy

I am soo scared for the experiments no matter how much time I do them, I always forget (organic expt)

pseudorachel

I'm betting the clove oil experiment will come up because they added a new part to it last year that's never been tested yet.

Bangdiggy

pseudorachel wrote: »

I'm betting the clove oil experiment will come up because they added a new part to it last year that's never been tested yet.

what part do you know?

cuprugby333

pseudorachel wrote: »

I'm betting the clove oil experiment will come up because they added a new part to it last year that's never been tested yet.

That new part being?

luftmensch

cuprugby333 wrote: »

That new part being?

Isolating the clove oil from the emulsion by solvent extraction is new. Before, we just had to know how to extract clove oil from cloves by steam distillation.

pseudorachel

cuprugby333 wrote: »

That new part being?

The first part is getting the clove oil and collecting the white emulsion.

the second part is separating the clove oil and the steam using liquid-liquid extraction with cyclohexane

cuprugby333

pseudorachel wrote: »

The first part is getting the clove oil and collecting the white emulsion.

the second part is separating the clove oil and the steam using liquid-liquid extraction with cyclohexane

Oh right I didn't know that was only added this year. Thanks

luftmensch

cuprugby333 wrote: »

Oh right I didn't know that was newly added. Thanks

Not only that but they took out a few experiments as well. My book is quite old, so I'm not sure which experiments I need not bother learning

cuprugby333

luftmensch wrote: »

Not only that but they took out a few experiments as well. My book is quite old, so I'm not sure which experiments I need not bother learning

I do titrations and organic Chem exp and generally avoid the q3s so can't help you there. But I think I have an updated book if the liquid-liquid cyclohexane extraction is in it

pseudorachel

Are any of ye doing the option?

emersyn

Does anyone know the answer to this question from my mock? I know it's probably a simple answer, I just can't get my head around what they're asking and my book isn't helping: "Name the series of coloured lines in the line emission spectrum of hydrogen corresponding to transitions of electrons from higher energy levels to the second energy level"

cuprugby333

emersyn wrote: »

Does anyone know the answer to this question from my mock? I know it's probably a simple answer, I just can't get my head around what they're asking and my book isn't helping: "Name the series of coloured lines in the line emission spectrum of hydrogen corresponding to transitions of electrons from higher energy levels to the second energy level"

Balmer series I believe

Bazinga_N

For anyone wondering, here's a quick guide to the changes to the chemistry course:

http://www.gillmacmillan.ie/AcuCustom/Sitename/DAM/060/LSMS_Chemistry_Changes_to_the_Experimental_Work.pdf

Bangdiggy

emersyn wrote: »

Does anyone know the answer to this question from my mock? I know it's probably a simple answer, I just can't get my head around what they're asking and my book isn't helping: "Name the series of coloured lines in the line emission spectrum of hydrogen corresponding to transitions of electrons from higher energy levels to the second energy level"

I had the same pre, it's Banner series

LordHypnos

predictions on what organic exp. will come up? reckon clove oil has a good chance as pseudorachel said on the previous page.

A97

EDIT: I just checked the curriculum and it appears that the Balmer series is the only one you need to know the name of.

I'm not too familiar with the Chemistry curriculum as I didn't do it for LC, but if an electron moves from a higher level to the 1st one, it's called the Lymann Series (produces UV light), higher level to 2nd level is called the Balmer Series (produces visible light), and higher to 3rd is called the Paschen Series (produces Infrared light).

Seaaan

pseudorachel wrote: »

Are any of ye doing the option?

I'm doing atmospheric and the one about the factory in.. Uh.. The one that makes the furnace linings (I can't even remember what is)

juniorcert

Anyone else dreading this? Chemistry's by far my worst subject and it's my last test as well so probably going to end the leaving cert on a down note

lc16_

Section A; (experiments my teacher has predicted)

Q1) Iron Tablets
Ethanoic Acid
Or Ethene/Ethyne

Q2) Clove oil
EDTA

Q3) Rates of reaction; hydrogen peroxide
Heat of nuetralisation
Anion tests


P.S. Can Le Chatelier's Principle exp come up in Section A?

lc16_

juniorcert wrote: »

Anyone else dreading this? Chemistry's by far my worst subject and it's my last test as well so probably going to end the leaving cert on a down note

Its my last exam too. It'll be hard to stay concentrated for the full 3 hours knowing its the last one but just remember it'll be all over after that so give it your all
You've got plenty of time between now & Tuesday to polish up on the definitions, theory & calculations so dont be dreading it, you'll be grand

emersyn

I have two more exams after Chemistry I'm on a week-long break from Wednesday to next Tuesday, then four exams in four days, can't wait

LordHypnos

lc16_ wrote: »

Section A; (experiments my teacher has predicted)

Q1) Iron Tablets
Ethanoic Acid
Or Ethene/Ethyne

Q2) Clove oil
EDTA

Q3) Rates of reaction; hydrogen peroxide
Heat of nuetralisation
Anion tests


P.S. Can Le Chatelier's Principle exp come up in Section A?

I'm assuming that's the acid base titration for ethanoic acid and not the organic preparation of ethanoic acid since that's off the course.

doubt Le Chatelier would come up in section a but I would expect equilibrium to feature somewhere on the paper

Bazinga_N

lc16_ wrote: »

P.S. Can Le Chatelier's Principle exp come up in Section A?

I mean there's nothing to say it can't but it's been reduced from three tests to one now and I really don't think there's enough for it to come up in A, but I'd say it'll be a part of the equilibrium long question.

alaandocs

lc16_ wrote: »

Section A; (experiments my teacher has predicted)

Q1) Iron Tablets
Ethanoic Acid
Or Ethene/Ethyne

Q2) Clove oil
EDTA

Q3) Rates of reaction; hydrogen peroxide
Heat of nuetralisation
Anion tests


P.S. Can Le Chatelier's Principle exp come up in Section A?

Ethene/ethyne won't come up in Q1 as its organic. It might have a chance in q.2 or somewhere else on the paper. Same with EDTA, it won't come up in q.2 but might in q.1.

The Le Chateliers exp. would probably be in section B as it has never come up in section A along with the redox ones but bits have in section B. That's not saying that this year will be the same they could put them in if they wanted, you wouldn't know.

lc16_

alaandocs wrote: »

Ethene/ethyne won't come up in Q1 as its organic. It might have a chance in q.2 or somewhere else on the paper. Same with EDTA, it won't come up in q.2 but might in q.1.

The Le Chateliers exp. would probably be in section B as it has never come up in section A along with the redox ones but bits have in section B. That's not saying that this year will be the same they could put them in if they wanted, you wouldn't know.

yeah, I got ethyne, ethene & EDTA mixed up in the questions! Thanks

And alright, cheers!

BrownTrout

emersyn wrote:

Does anyone know the answer to this question from my mock? I know it's probably a simple answer, I just can't get my head around what they're asking and my book isn't helping: "Name the series of coloured lines in the line emission spectrum of hydrogen corresponding to transitions of electrons from higher energy levels to the second energy level"

Higher to 2nd is Balmer
Higher to 1st is Lymen
Higher to 3rd is Paschen

hurler97

lc16_ wrote:

P.S. Can Le Chatelier's Principle exp come up in Section A?

Yes it can and it would more than likely appear on Q3

lc16_

Hows everyone set for Chemistry?

Knowing its my last exam is clearly not helping me focus for the evening in any way shape or form

alaandocs

lc16_ wrote: »

Hows everyone set for Chemistry?

Knowing its my last exam is clearly not helping me focus for the evening in any way shape or form

Should be good to go, experiments are where I'm focusing atm

juniorcert

lc16_ wrote: »

Hows everyone set for Chemistry?

Knowing its my last exam is clearly not helping me focus for the evening in any way shape or form

Same, I'm finding it very hard to concentrate or to care very much anymore when I know freedom is so close

Seaaan

The fact that it's in the afternoon leaves me thinking I can put off cramming until tomorrow. Bad idea I think

lc16_

Seaaan wrote: »

The fact that it's in the afternoon leaves me thinking I can put off cramming until tomorrow. Bad idea I think

^^^Exactly what my mind is playing at currently

Seaaan

They better not spring surprises on us for this either; physics had them! Iron tablets and Ethene/Ethyne please.

WorthlessPeon

Seaaan wrote: »

They better not spring surprises on us for this either; physics had them! Iron tablets and Ethene/Ethyne please.

Ideal experiments right there, throw in the relative atomic mass of a volatile liquid one and we're away!

emersyn

If ethene/ethyne comes up I'll cry with joy

louisoc

Anyone else given phenylmethanol the slip? I know it's irresponsible to avoid things, but I just can't hack that experiment - it didn't work when we did it in class, and the minutiae of the procedure are unbearable. Feeling adventurous completely ignoring it, but I'm confident with my titrations and the other miscellaneous experiments.

LordHypnos

louisoc wrote: »

Anyone else given phenylmethanol the slip? I know it's irresponsible to avoid things, but I just can't hack that experiment - it didn't work when we did it in class, and the minutiae of the procedure are unbearable. Feeling adventurous completely ignoring it, but I'm confident with my titrations and the other miscellaneous experiments.

absolutely, willing to take that chance

DownOneTourist

LordHypnos wrote: »

absolutely, willing to take that chance

it's quite embarrassing but after 2 years of chem I have no idea what you two are talking about. I'd better sort that out. perhaps tomorrow morning

LordHypnos

DownOneTourist wrote: »

it's quite embarrassing but after 2 years of chem I have no idea what you two are talking about. I'd better sort that out. perhaps tomorrow morning

it's the mandatory experiment they added for last year's exam.
here's a full list of updates to the course;
http://www.gilleducation.ie/AcuCustom/Sitename/DAM/060/LSMS_Chemistry_Changes_to_the_Experimental_Work.pdf

DownOneTourist

LordHypnos wrote: »

it's the mandatory experiment they added for last year's exam.
here's a full list of updates to the course;
http://www.gilleducation.ie/AcuCustom/Sitename/DAM/060/LSMS_Chemistry_Changes_to_the_Experimental_Work.pdf

it actually rings a bell now. thanks for the link. I remember aqueous layer and organic layer.

louisoc

DownOneTourist wrote: »

it actually rings a bell now. thanks for the link. I remember aqueous layer and organic layer.

aqueous and organic layer are a new part of the clove oil experiment, not the phenylmethanol. I'd say THAT one is definitely worth knowing, given that I think it's the only thing on the entire course right now that's never been examined!

hurler97

louisoc wrote:

Anyone else given phenylmethanol the slip? I know it's irresponsible to avoid things, but I just can't hack that experiment - it didn't work when we did it in class, and the minutiae of the procedure are unbearable. Feeling adventurous completely ignoring it, but I'm confident with my titrations and the other miscellaneous experiments.

We referred to it as the benzoic acid experiment so maybe other people who don't recognise phenylmethanol will know what the experiment is now

Misty_01

Can any one explain the 2015 Q11 B to me , the part where it asks if the reaction is exo or endothermic ???? Thanks.

daraghwal

Does anyone have a list of the experiments that come up in question 1 and 2? I know 1 is vol analysis and 2 is organic but I'm just not sure which ones they can potentially ask. Also is it alright to leave out electrochemistry? Just have a look over it maybe?

louisoc

Misty_01 wrote: »

Can any one explain the 2015 Q11 B to me , the part where it asks if the reaction is exo or endothermic ???? Thanks.

From the graph you can see that the Kc rises exponentially as temperature increases, that means that as Kc increases, the left side becomes less concentrated and the right side becomes more concentrated. (because Kc is right side over left side, if denominator is smaller and the numerator is bigger the number is bigger). Temperature increase always drives the endothermic reaction (to counteract stress; Le Chatelier's) which means the forward reaction - the dissociation of gas A - is endothermic.

Bangdiggy

Misty_01 wrote: »

Can any one explain the 2015 Q11 B to me , the part where it asks if the reaction is exo or endothermic ???? Thanks.[/quote
From the graph you can see that Kc increases as temperature increases. And you should know that an increase in temperature always favours the endothermic reaction. Now if you look at the equation you see that if the top is exothermic and you ↑temp then the the bottom(backward) reaction is endothermic BUT... it says the dissociation of A, therefore if bottom(reverse) is endothermic then that means your making A and not dissociating it, So then that means the top(forward) reaction will be Endothermic

Oh dear, I don't think I would understand myself, so I hope you understand

lc16_

Q1) Iron Tablets exp
Q2) Ethene/Ethyne
Q3) Rates of reaction exp
Q4) Short qs heavily on defintions
Q5) Trends in periodic table & bonding
Q6) Thermochemistry equations & Fuels, hydrocarbon definitions
Q7) Long water q
...Q11) A- Gas laws & calculations
B- Equilibrium defs & calc
That would be an absolute beauty of a paper