General thoughts: HSC chemistry 2015 (4 Viewers)

[malcolm21]

(B) is clearly the answer. A condensation polymer can be two monomers long (dimer).

but do the two monomers combine to give that dimer? i cant remember off the top of my head, i went with d like most people

 

[IamKirby]

(B) is clearly the answer. A condensation polymer can be two monomers long (dimer).

Exactly, a dimer, which is not a polymer. A polymer has many units.

 

[Librah]

Exactly, a dimer, which is not a polymer. A polymer has many units.

Apparently a dimer is considered a polymer of degree 2, even if it's formed from two dissimilar monomers that make it.

 

[Bozzin8R]

The answer to the polymer MC was D, 100% it was.

 

[IamKirby]

Apparently a dimer is considered a polymer of degree 2, even if it's formed from two dissimilar monomers that make it.

I highly doubt this would be the case in our exam but I guess it's not beyond the Board.

 

[Fizzy_Cyst]

(B) is clearly the answer. A condensation polymer can be two monomers long (dimer).

A dimer is an oligomer, not a polymer. In a polymer, the number of monomers is not fixed.

 

[Torque]

I just decidied to do a wiki search, https://en.wikipedia.org/wiki/Dimer_(chemistry). Answer is probably in fact B for q11.

"In chemistry, an oligomer is a molecular complex that consists of a few monomer units, in contrast to a polymer, where the number of monomers is, in principle, not limited."

Wikipedia may not be a fully reliable site, but I dont think B would qualify as a polymer if it a dimer.

https://en.wikipedia.org/wiki/Oligomer

 

[Librah]

Lmao tbh i'm sick of doing HSC chem, just wait for BOSTES to post solutions.

 

[malcolm21]

for the polymer mc everyones getting worked up over, a less technical way i decided between b and d is that c and d were really similar structures, and the board usually wouldnt waste 2 similar answers for no reason, so i looked between c and d and chose d lol

 

[Anousha]

Is electrophoresis a type of chromatography ? (I didn't do this for the 7 marker just asking for a friend)

 

[IamKirby]

No

 

[HecticLad]

GUYSSS, who knows the definite answers to multiple choice: 10,15,19 ?

A, C, C

 

[Bozzin8R]

GUYSSS, who knows the definite answers to multiple choice: 10,15,19 ?

D, C, C

 

[tryhard1232]

Guys what raw mark would align to 87? I think this year's aligning won't be as bad as last year

 

[marauder7]

holy shit was it citric acid

 

[marauder7]

how many marks am i going to lose for reading citric acid as acetic acid for the 4 mark titration calculation question?

wtf was it citric?? Hoenstly was it citric??

 

[kawaiipotato]

wtf was it citric?? Hoenstly was it citric??

Yep

 

[apurba]

wtf was it citric?? Hoenstly was it citric??

yeah man, i'm not trolling. i just threw way my hopes of getting a band 6 cos of that question aha.

 

[Bozzin8R]

What did people get for that question? I definitely used citric, and 0.060 mol/L rings a bell for some reason. Anyone want to confirm/disagree?

 

[kawaiipotato]

What did people get for that question? I definitely used citric, and 0.060 mol/L rings a bell for some reason. Anyone want to confirm/disagree?

I got 0.181 (3sf.) lol
Was the question something like 25mL citric at 0.100mol/L reacts with sodium hydroxide and avg sodium hydroxide was 41.5mL?