General thoughts: HSC chemistry 2015 (5 Viewers)

[invisible036]

do they do it in maths? i was asking around from the 2u test and everyone shut me down

My teacher who is a previous HSC marker also said that.

http://news.boardofstudies.nsw.edu....1/UPDATE--Advice-for-HSC-written-examinations

 

[nerdz1]

It did say it reached equilibrium. "The mixture was allowed to reach equilibrium" and the initial volume is 1L

http://community.boredofstudies.org...684_956764334395283_8188749964911151150_n.jpg

I might be interpreting it wrong but I don't think it was equilibrium at 1L.

Edit: My bad

 

[sameermu]

They haven't worded it very well but before any question is asked, it says "The mixture is allowed to reach equilibrium". Thus certain people will interpret that as saying it reached equilibrium at 1L...

 

[Gabriel Moussa]

Fuck chem wallah

 

[Anousha]

WOOH DIDNT STUDY ES AND MS and it wasn't in it (option: forensic chemistry)

 

[wizzledonker]

WOOH DIDNT STUDY ES AND MS and it wasn't in it (option: forensic chemistry)

Would have helped if you mentioned that bit about mass spec being useful alongside HPLC, you might have done but it still helps to have a broad knowledge.

 

[Anousha]

Would have helped if you mentioned that bit about mass spec being useful alongside HPLC, you might have done but it still helps to have a broad knowledge.

I knew MS and ES roughly but not in detail ))

 

[Emmo121]

Lol did anyone do a title for the line graph ? and do you need to ?

 

[SilentWaters]

That equilibrium question for industrial chem is an interesting one. Typically, only a change in temperature will affect the value of K.

The initial and final values of 10 and 11 respectively (2 sf) seem pretty disparate to me.

 

[Kaido]

Lol did anyone do a title for the line graph ? and do you need to ?

Wrote it for safety.

How is 4 marks awarded to a graph. Like wtf, srs

 

[malcolm21]

Wrote it for safety.

How is 4 marks awarded to a graph. Like wtf, srs

ikr 4 marks is ridiculous, by the way for the x axis did you guys put the first year at x=0, i was wondering whether i should do that or not but i didn't, so theres a 1 unit gap between the x=0 and x=1950 or whatever the year was

 

[Librah]

Wrote it for safety.

How is 4 marks awarded to a graph. Like wtf, srs

3 for correct axes and APPROPRIATE spacing of units (graph should fit most of the space) and 1 for the graph itself. Seems reasonable to me.

 

[Crisium]

Lol did anyone do a title for the line graph ? and do you need to ?

Yeah and I just called it changes in the ozone concentration above the Antartic over the past 50 years or something along those lines

 

[Emmo121]

3 for correct axes and APPROPRIATE spacing of units (graph should fit most of the space) and 1 for the graph itself. Seems reasonable to me.

So, Title doesn't matter ? lol

 

[Librah]

So, Title doesn't matter ? lol

Doubt it, maybe though.

 

[Crisium]

This is the condensation polymerisation of 1,4 butanedioic acid and ethylene glycol.

First step produces (B) which is ethylene glycol succinate (not a polymer), this then forms polyethylene glycol succinate (PES) which IS NOT (D), rather it is D without one of the 'O' atoms on either the LHS or RHS.

I maybe wrong, but I don't see there being a clear answer :\

Personally, I am thinking B is more correct as water is eliminated during this process and it involves two monomers joining :\

This is reassuring

I went along with the same thought process

+ Check your email

 

[Librah]

Yeah ok nah, i just had a look over this years exam, it's easier than last years.

 

[Anousha]

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

 

[SilentWaters]

I maybe wrong, but I don't see there being a clear answer :\

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

EDIT: Yes, okay if you want to be incredibly nit-picky, you could say (B) is an oligomer (a molecule consisting of only a few repeating subunits - see http://goldbook.iupac.org/O04286.html). IMO it boils down to which answer is 'more' correct - a lame excuse for BOSTES getting sloppy with the chemistry.

 

[Librah]

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