Exam Suggested Solutions

[Aba]

1-amino-ethane should work.

and the diprotic bit didnt matter, i got the same answer and i completely ignored the diprotic bit.

exam was easy, weird, but easy.

some 1 mark questions were weird, new babies for checkpoints 09'

[ed_saifa]

1-amino-ethane should work.

and the diprotic bit didnt matter, i got the same answer and i completely ignored the diprotic bit.

exam was easy, weird, but easy.

some 1 mark questions were weird, new babies for checkpoints 09'

I think 1-amino-ethane won't be right because you don't need the 1.

[Mao]

lol how important are the hyphens when naming?

i think i wrote

2-methyl 5-chloroheptane

no hyphen between the methyl and 5, does it matter?

that should be fine for vce standard

[bucket]

Hyphens are really important! But you didnt need a hyphen between those two!
The commas are used when theres more than one uhm, group, in the molecule
ie. 2,3 dimethylbutane or something.

[Synesthetic]

I'd love to hear other opinions of this issue. It relates to question 4 part b - where it was given that a C13 NMR spectrum had THREE lines. Now, most people have taken it to mean THREE carbon environments (and hence 2-methylpropan-1-ol) (as in Mao's solutions of course).

But - I probably read too far into it - I wrote "TMS would constitute one of the peaks, hence there are TWO carbon environments", and therefore iv) would be 2-methylpropan-2-ol. So I emphasised the fact that one of the peaks was that of TMS, obviously not signifying a third carbon environment.

Thoughts? I'm annoyed at the wording really, I bet the test designer didn't think of this...

[bucket]

I'd love to hear other opinions of this issue. It relates to question 4 part b - where it was given that a C13 NMR spectrum had THREE lines. Now, most people have taken it to mean THREE carbon environments (and hence 2-methylpropan-1-ol).

But - I probably read too far into it - I wrote "TMS would constitute one of the peaks, hence there are TWO carbon environments", and therefore iv) would be 2-methylpropan-2-ol.

Thoughts? I'm annoyed at the wording really, I bet the test designer didn't think of this...

Wow thats a tricky one, the question COULD have been read like this O_O.
Maybe all of us who did three C environments are wrong??
>.<

[Aba]

I'd love to hear other opinions of this issue. It relates to question 4 part b - where it was given that a C13 NMR spectrum had THREE lines. Now, most people have taken it to mean THREE carbon environments (and hence 2-methylpropan-1-ol).

But - I probably read too far into it - I wrote "TMS would constitute one of the peaks, hence there are TWO carbon environments", and therefore iv) would be 2-methylpropan-2-ol.

Thoughts? I'm annoyed at the wording really, I bet the test designer didn't think of this...

Wow thats a tricky one, the question COULD have been read like this O_O.
Maybe all of us who did three C environments are wrong??
>.<

i doubt it, hopefully!

[Mao]

seriously guys do you want to challange me to a chem off?
get back to me once uve figured this out yeh?

a substance with the formula 'C5H8O' is known to be a cyclic ketone, draw all possible structural isomers, and indicate if those, if any, can exist as stereoisomers.
piece of cake

yep

cyclopetanone

methylcyclobutanone (there's 2 of these)

ethylcyclopropanone

dimethylcyclopropanone



dont care how good you think you are, but you got pwnt on that mark.

[Aba]

lol thats fine, i wrote aminoethane, i was just in dribbling-after-exam-mode (hahaha hyphen that)


too biochemy, this new course is gonna make all the chem kids soft.

[Aba]

wasnt there a double dilution for the manganese question, meaning the percentage of manganese was around 18%??? thats wat ma friends says, i think he was right, cause his teacher said the same i think!

it was actually dissolve -> take aliquot -> dilute -> take aliquot

when u take an aliqout u r takin a certain amount of mole out, hence there is a dilution and an 'aliqout dilution' that need to be taken into account, ma friend said that, the only reason i think is cause his teacher said it

can someone confirm this, my teachers friend said it and i want to knowwwwww

[Mao]

I'd love to hear other opinions of this issue. It relates to question 4 part b - where it was given that a C13 NMR spectrum had THREE lines. Now, most people have taken it to mean THREE carbon environments (and hence 2-methylpropan-1-ol) (as in Mao's solutions of course).

But - I probably read too far into it - I wrote "TMS would constitute one of the peaks, hence there are TWO carbon environments", and therefore iv) would be 2-methylpropan-2-ol. So I emphasised the fact that one of the peaks was that of TMS, obviously not signifying a third carbon environment.

Thoughts? I'm annoyed at the wording really, I bet the test designer didn't think of this...

yes, but the second reaction is against this. as a carboxylic acid is produced, it has to be a 1-hydroxy. the isomer you are talking about does not fit.

[Mao]

wasnt there a double dilution for the manganese question, meaning the percentage of manganese was around 18%??? thats wat ma friends says, i think he was right, cause his teacher said the same i think!

it was actually dissolve -> take aliquot -> dilute -> take aliquot

when u take an aliqout u r takin a certain amount of mole out, hence there is a dilution and an 'aliqout dilution' that need to be taken into account, ma friend said that, the only reason i think is cause his teacher said it

can someone confirm this, my teachers friend said it and i want to knowwwwww

there is no pipette dilusion. it does not exist. [the pipette fills with the solution you are pipetting, nothing else, not extra water, nothing]

[ilovenmr]

yeaaah good point synesthetic

marks for everyone maybe cause it's not specific about peaks as opposed to environments

or maybe two accepted answers

[Aba]

wasnt there a double dilution for the manganese question, meaning the percentage of manganese was around 18%??? thats wat ma friends says, i think he was right, cause his teacher said the same i think!

it was actually dissolve -> take aliquot -> dilute -> take aliquot

when u take an aliqout u r takin a certain amount of mole out, hence there is a dilution and an 'aliqout dilution' that need to be taken into account, ma friend said that, the only reason i think is cause his teacher said it

can someone confirm this, my teachers friend said it and i want to knowwwwww

there is no pipette dilusion. it does not exist. [the pipette fills with the solution you are pipetting, nothing else, not extra water, nothing]

but a certain portion of the mole is being taken out, therefore, u need to x (100/20) and (1000/20) to account for this. I didnt do this though
 dissolve -> take aliquot -> dilute -> take aliquot
---- take aliqout is removing a certain proprotion of mole, calculate for this, then there was a dilution, calculate for this and an aliqout taken from the solution, so calculate for this??

[Synesthetic]

I'd love to hear other opinions of this issue. It relates to question 4 part b - where it was given that a C13 NMR spectrum had THREE lines. Now, most people have taken it to mean THREE carbon environments (and hence 2-methylpropan-1-ol) (as in Mao's solutions of course).

But - I probably read too far into it - I wrote "TMS would constitute one of the peaks, hence there are TWO carbon environments", and therefore iv) would be 2-methylpropan-2-ol. So I emphasised the fact that one of the peaks was that of TMS, obviously not signifying a third carbon environment.

Thoughts? I'm annoyed at the wording really, I bet the test designer didn't think of this...

yes, but the second reaction is against this. as a carboxylic acid is produced, it has to be a 1-hydroxy. the isomer you are talking about does not fit.

Good point - thanks for pointing that out.

I suppose that's another four marks gone (2 for part i, another 2 for part iv) - I doubt they'd align consequential marks to this.