Unit 3 Questions MEGATHREAD :)

[thushan]

Nup. No need to write heat on top of the arrow.

[nacho]

would
2methyl-propan-1-ol be accepted if the given answers are:


• methylpropan–1–ol
• methyl–1–propanol
• 2–methyl–1–propanol

[Water]

Water's question


From 2008 VCAA.

4-aminophenol absorbs less strongly than paracetamol onto the stationary phase of this TLC plate. Predict whether the Rf Value of 4-aminophenol in this analysis is greater or smaller than that of paracetamol, giving a reason for your choice.


My Answer: Greater than paracatamol as 4-aminophenol would desorb greater than adsorb thereby move along the mobile phase easier.

VCAA Answer: Greater, moves further from origin.



Would my answer be correct xD?


1 mark question btw.

[RobM8]

Nacho, only
• methylpropan–1–ol
• methyl–1–propanol
are correct as it is wrong nomenclature to put a 2 in front of the methyl - as it is the only place that it can occupy.

[RobM8]

Water's question


From 2008 VCAA.

4-aminophenol absorbs less strongly than paracetamol onto the stationary phase of this TLC plate. Predict whether the Rf Value of 4-aminophenol in this analysis is greater or smaller than that of paracetamol, giving a reason for your choice.


My Answer: Greater than paracatamol as 4-aminophenol would desorb greater than adsorb thereby move along the mobile phase easier.

VCAA Answer: Greater, moves further from origin.



Would my answer be correct xD?

Your answer is messy but it is essentially saying the same thing.
I wouldn't say it desorbs greater than adsorbs...
Maybe 'Greater than paracatamol as 4-aminophenol does not adsorb to the stationary phase as strongly and hence spends more time in the mobile phase resulting in greater displacement from the origin and a higher Rf value'.

[jasoN-]

Nacho, only
• methylpropan–1–ol
• methyl–1–propanol
are correct as it is wrong nomenclature to put a 2 in front of the methyl - as it is the only place that it can occupy.

no clue why they didn't just call it 2-butanol

[RobM8]

Because methylpropan-1-ol and butan-2-ol are structural isomers
    C
    |
C-C-C is different to C-C-C-C

[nacho]

Nacho, only
• methylpropan–1–ol
• methyl–1–propanol
are correct as it is wrong nomenclature to put a 2 in front of the methyl - as it is the only place that it can occupy.

the 2-methyl-1-propanol is the answer given by vcaa, and the methyl group could hang off the first carbon atom
except i was just wondering
since i wrote 2-methyl, am i incorrect in saying propan-1-ol and should i have to say 1-propanol

also, yea water your ans is correct, except just being pedantic - it technically doesnt move along the mobile phase, it just bonds to the mobile phase - doesn't it? (wait, is that the same thing?...)
It moves up the stationary phase, i would just say 'further away from the origin'

btw, what mark did u get on 08, water?

[Water]

nacho, I did the 08 exam at 1:30am, half asleep, back home from watching a recital and eating pizza..... Inevitably, I received 83%...a very poor grade ):


+ for that question, I marked it wrong because it didn't align with VCAAs, not sure if I was being too harsh.

[RobM8]

So the answer had a 2 infront of the methyl?
Why? There is only one possible carbon for the methyl to be on?

The methyl group can't be on the first carbon atom otherwise it becomes butanol ?

To answer the original aim of your question: propan-1-ol and 1-propanol are saying the same thing.

[luken93]

Yeah, but the assessor's have stated that as long as it is named within the IUPAC ruling and is clear what you are naming, it isn't wrong. Hence. you are able to put 2-methyl or just methyl - as both imply the same meaning.

[Water]

A new question, from the 2008 VCAA.


Is the IO4- (aq) ion acting as an oxidant or reductant? Explain your choice.


My Answer: Oxidant, as it causes the reduction reaction.



VCAA: Oxidant, the oxidation number of I decreases from +7 to +5.



Was my answer too herpy derpy? It is another 1 mark question. I Don't know when the VCAA wants a general answer or a deep answer. God >_<!

[RobM8]

Yeah, but the assessor's have stated that as long as it is named within the IUPAC ruling and is clear what you are naming, it isn't wrong. Hence. you are able to put 2-methyl or just methyl - as both imply the same meaning.

Yeah.

Always give specific answers Water; it is a minor discrepancy but you have given a very general reason and have more said what an oxidant does not why the ion is acting as an oxidant.

[nacho]

damn, ya beat me by 1 mark..
i got every aspiriin question wrong, we never did an aspirin SAC, our last sac was on polymers..
4 multiple choice errors, that def could have been handled better..

just realised, that it would indeed be butanol, hm..


uh in regards to your oxidation quesiton, i think its always best to write like what it reduces, or that there is a change in the oxidation number

can we use 'hydrogen environments' and 'proton environments' interchangebly?

[RobM8]

1H NMR and proton NMR are the same thing and can be used interchangeably.

1H = a proton.