Exam Suggested Solutions

[ganges]

FCK!! the significant figurees were so annoying!!!

Its really hard to keep track of ur significant figures in the middle of your exam!!!!

Are the examiners strict about this?

[jay.]

oh no i put 6-methyl, 3-chloroheptane is that wrong

[Collin Li]

the molecule is called 3-chloro,6-methylheptane!
i honestly dont think i dropped a mark!!
only coz i owned biol last year though
 nooobs

We've been through this already:

http://butane.chem.uiuc.edu/cyerkes/Chem104A_BFA05/Genchemref/nomenclature_rules.html

"The halogen is treated as a substituent on an alkane chain. The halo- substituent is considered of equal rank with an alkyl substituent in the numbering of the parent chain."

The answer is 5-chloro-2-methylheptane.

Also, your comma is incorrect, it should be a hyphen.

[Mao]

the molecule is called 3-chloro,6-methylheptane!
i honestly dont think i dropped a mark!!
only coz i owned biol last year though
 nooobs

that's wrong, "infraredismybitch"

it is 5-chloro-2-methylheptane

or the less correct version

2-methyl-5-chloroheptane

pwnt

[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!

[bucket]

the molecule is called 3-chloro,6-methylheptane!
i honestly dont think i dropped a mark!!
only coz i owned biol last year though
 nooobs

No, its not!
You have to count from the end of the chain CLOSEST to the functional group!
The thing that overrides this is the presence of a double bond!!

edit*
thankyou coblin!

(i lost one mark here Tongue forgot that it was diprotic

Uhm, with this question (question 8, short answer) I didn't include anything to do with the thing being diprotic in my calculations, and I ended up with the same answers that Mao posted. (I'm assuming he posted the corrected answer)
From what I remember, I did use mol ratios, but nothing to do with something being diprotic, just that 2 NaOHs would react with one of the acid, which was common sense >.<

[Mao]

(i lost one mark here Tongue forgot that it was diprotic

Uhm, with this question (question 8, short answer) I didn't include anything to do with the thing being diprotic in my calculations, and I ended up with the same answers that Mao posted. (I'm assuming he posted the corrected answer)
From what I remember, I did use mol ratios, but nothing to do with something being diprotic, just that 2 NaOHs would react with one of the acid, which was common sense >.<

yeah, because the mole ratio is 1:2 makes it diprotic
and i totally forgot about that and just assumed 1:1 xD [lol i'm an idiot]

[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!

nope, just thoroughly checked mine.

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

[monicak]

Thanks for typing up all the solutions and question 1. I've checked it again and I know what I stuffed up [stupid mistake]..   Hope I get at least 1 consequential mark from part c.. Would you be able to type up the text of SA question 8? I can't remember if that's the answer that I got  

[Aba]

i owned the absolute shites outa that exam!!!
hahah im sooo happy i was getting nervous b4 it...but wat for??

that was honestly a joke

[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

[Aba]

does ne1 reckon that for the systematic naming ull get the mark if u wrote 1-aminoethane???
coz thats wat i did:S stupid really

[bucket]

does ne1 reckon that for the systematic naming ull get the mark if u wrote 1-aminoethane???
coz thats wat i did:S stupid really

yes.

[infraredismybitch]

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

[vce01]

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?