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

Appmaths97

BrownTrout wrote: »

I had a gut feeling that Benzoic was going to show face again, lucky I revised it!

they did the same for physics. one of the questions was poorly answered last year and they put it up again because of that

LordHypnos

Appmaths97 wrote: »

they did the same for physics. one of the questions was poorly answered last year and they put it up again because of that

guess that's the only way they could repeat an organic experiment without teachers and students getting on their a**

bookworm20

why is there no yellow line in hydrogen spectrum?
What physical property does are hydrocarbons isolated by?
What was the balanced chemical equation in q10 b?

LordHypnos

bookworm20 wrote: »

why is there no yellow line in hydrogen spectrum?
What physical property does are hydrocarbons isolated by?
What was the balanced chemical equation in q10 b?

the first balanced equation I got was;
4a + b + c -> 4x +2y + z

bookworm20

LordHypnos wrote: »

the first balanced equation I got was;
4a + b + c -> 4x +2y + z

yaaay!! i got that too!

Appmaths97

bookworm20 wrote: »

why is there no yellow line in hydrogen spectrum?
What physical property does are hydrocarbons isolated by?
What was the balanced chemical equation in q10 b?

they are isolated by their boiling points

bookworm20

Appmaths97 wrote: »

they are isolated by their boiling points

thanks, thats what i said too

medhopeful16

Appmaths97 wrote: »

they are isolated by their boiling points

Could it have something to do with the carbon chain length. I said about the boiling points too but I remember thinking that the question was phrased strangely and could be referring to that.

bookworm20

medhopeful16 wrote: »

Could it have something to do with the carbon chain length. I said about the boiling points too but I remember thinking that the question was phrased strangely and could be referring to that.

my teacher said specifically not to say carbon chain length when asked that question....though it was phrased quite strangely

medhopeful16

bookworm20 wrote: »

my teacher said specifically not to say carbon chain length when asked that question....though it was phrased quite strangely

Well that settles that, hopefully I won't lose the marks for mentioning it
Did anybody know the answer why there was no yellow line?

LordHypnos

after deducting marks for answers I know are wrong, I'm still at A1. Honestly, coming out of the exam at 4:11pm(!) I was heartbroken because of Q2 but now I realise that it wasn't all that bad because every other question was fairly straightforward! Might make the A1 after all

medhopeful16

LordHypnos wrote: »

after deducting marks for answers I know are wrong, I'm still at 98%. Honestly, coming out of the exam at 4:11pm(!) I was heartbroken because of Q2 but now I realise that it wasn't all that bad because every other question was fairly straightforward! Might make the A1 after all

'There's always one' they say. They were right.

LordHypnos

medhopeful16 wrote: »

'There's always one' they say. They were right.

yeah I know, just kind of shocked because I did so poorly in chemistry last year, barely passed the mocks

Imaginary Friend

So happy with that paper, especially after the disaster that was Physics.

What was the name of the laboratory technique for purifying benzoic acid? I said recrystallisation with vacuum filtration but I wasn't really sure what they were looking for ...

I got Kc as 196,000 (very nearly forgot to divide by 50 :S), % (w/v) 4.8%, sulfur in excess with 16g unused, 7.84 L gaseous products and like 9.4 g solid products.

Did Q1, 2, 4, 5, 6, 7, 8, 9, 10, 11.

medhopeful16

LordHypnos wrote: »

yeah I know, just kind of shocked because I did so poorly in chemistry last year, barely passed the mocks

You're a repeater? I'll probably be in your position next year. Medicine isn't looking good after the exams, thankfully Chemistry didn't go so bad but the rest were dodgy. What are you going for if you don't mind me asking?

bookworm20

Imaginary Friend wrote: »

What was the name of the laboratory technique for purifying benzoic acid? I said recrystallisation with vacuum filtration but I wasn't really sure what they were looking for ...

yea i said recrystallisation using hot and cold filtration

LordHypnos

medhopeful16 wrote: »

You're a repeater? I'll probably be in your position next year. Medicine isn't looking good after the exams, thankfully Chemistry didn't go so bad but the rest were dodgy. What are you going for if you don't mind me asking?

I was set on commerce(accounting) in galway but I might just take a year out instead.

daraghwal

LordHypnos wrote: »

I was set on commerce(accounting) in galway but I might just take a year out instead.

Any tips for repeating? I'm repeating next year for veterinary

LordHypnos

daraghwal wrote: »

Any tips for repeating? I'm repeating next year for veterinary

would you be in a separate class to the 6th years? I feel that really helped. Teachers are focused solely on you and most things will seem like revision so studying is much easier. That being said you're responsible for your own study so make sure you don't lose track and the best part about repeating is you can drop core subjects ie. English, Maths and Irish. You can do less subjects, I did the minimum, 6, including LCVP and German meaning there was less pressure and less subjects to study for. I tried taking up Ag Science at the start but I couldn't get my head around the jargon so I dropped it after a few weeks. Personally I wouldn't advise taking up subjects unless you're short. Make sure you work from day 1 and maintain through christmas, the mocks and try avoid being absent from school despite what the rest of the repeats do/think. Overall it was a great experience and when you think of your friends being at college and you stuck doing the LC again, just remember a year spent now could benefit you hugely in the future!

A97

medhopeful16 wrote: »

Well that settles that, hopefully I won't lose the marks for mentioning it
Did anybody know the answer why there was no yellow line?

Honestly I have no clue if this is correct. I didn't even do Chemistry in school but I would guess that there is no yellow line because the energy released by the electron moving from any higher electron shell to the second one does not correspond to a frequency/wavelength that would release yellow light.

Do you know anything about the Rydberg constant? There's a formula for working out each possible frequency but you might not have been expected to know that.

daraghwal

LordHypnos wrote: »

would you be in a separate class to the 6th years? I feel that really helped. Teachers are focused solely on you and most things will seem like revision so studying is much easier. That being said you're responsible for your own study so make sure you don't lose track and the best part about repeating is you can drop core subjects ie. English, Maths and Irish. You can do less subjects, I did the minimum, 6, including LCVP and German meaning there was less pressure and less subjects to study for. I tried taking up Ag Science at the start but I couldn't get my head around the jargon so I dropped it after a few weeks. Personally I wouldn't advise taking up subjects unless you're short. Make sure you work from day 1 and maintain through christmas, the mocks and try avoid being absent from school despite what the rest of the repeats do/think. Overall it was a great experience and when you think of your friends being at college and you stuck doing the LC again, just remember a year spent now could benefit you hugely in the future!

I will be in classes with other 6th years next year. I will be dropping english and irish and taking on ag science. I live on a farm and am really interested in the ag science so I think it will go ok. I did biology myself since 5th year and that's actually one of my best this year. Next year my subjects will be maths, technology, ag science, chemistry and french is school and business and biology outside. Thanks for the advice.

alaandocs

A97 wrote: »

Honestly I have no clue if this is correct. I didn't even do Chemistry in school but I would guess that there is no yellow line because the energy released by the electron moving from any higher electron shell to the second one does not correspond to a frequency/wavelength that would release yellow light.

Do you know anything about the Rydberg constant? There's a formula for working out each possible frequency but you might not have been expected to know that.

No nothing as complex as that I'm afraid. All we deal with is E=fh which isn't the most accurate but your answer is correct is presume.

bookworm20

A97 wrote: »

there is no yellow line because the energy released by the electron moving from any higher electron shell to the second one does not correspond to a frequency/wavelength that would release yellow light.

Thats is exactly what I said but dont really know if its right or not

Badgerrr7

Can somebody do the equilibrium question. Pretty sure i went wrong in calculation. Ended up with something in the 3000's and I amnt confident with that.

LordHypnos

Badgerrr7 wrote: »

Can somebody do the equilibrium question. Pretty sure i went wrong in calculation. Ended up with something in the 3000's and I amnt confident with that.

Many claiming 196000, can't remember what I got but if you did the method right but made a calculation error you'd probably get most of the marks, don't worry.

louisoc

Badgerrr7 wrote: »

Can somebody do the equilibrium question. Pretty sure i went wrong in calculation. Ended up with something in the 3000's and I amnt confident with that.

Here ya go dude:

http:// imgur. com/ajmnDST

Remove spaces cause apparently I'm too new a user to be allowed share links

Also in Q2 when it asked to deduce which liquid evaporated the quickest, "based on this observation" - I just said ethanal, were they looking for a big spiel on boiling points and stuff?

LordHypnos

louisoc wrote: »

Here ya go dude:

http:// imgur. com/ajmnDST

Remove spaces cause apparently I'm too new a user to be allowed share links

Also in Q2 when it asked to deduce which liquid evaporated the quickest, "based on this observation" - I just said ethanal, were they looking for a big spiel on boiling points and stuff?

doubt it, there was 12 marks going for it including the fehling's reagent test which would probably be worth 9 marks leaving 3 marks for ethanal

LordHypnos

anyone know why the inside of the paper was white and not pink?

louisoc

LordHypnos wrote: »

doubt it, there was 12 marks going for it including the fehling's reagent test which would probably be worth 9 marks leaving 3 marks for ethanal

Niceeeeeee

Having done a very rough calculation of my result, I'm semi-confident I got ~360/400 - absolutely at the mercy of the examiner which way the grade goes now

LordHypnos

louisoc wrote: »

Niceeeeeee

Having done a very rough calculation of my result, I'm semi-confident I got ~360/400 - absolutely at the mercy of the examiner which way the grade goes now

I'd say it will be marked roughly given the generally good reaction to the paper