2003 HSC Solustions (1 Viewer)

[ben7]

Does anybody have these and where can i get them. I have 2001 soltutions in some book, 2002 standards package but no 2003 solutions, in particular Q17c Q20 and Q23b so far.. lol

Thanks
Ben

 

[Paroissien]

Does anybody have these and where can i get them. I have 2001 soltutions in some book, 2002 standards package but no 2003 solutions, in particular Q17c Q20 and Q23b so far.. lol

Thanks
Ben

I have the answers in Success One book, and quickly the answers are:
17c: polymerisation is a random process, and a range of chain lengths form

20: Firstly say how useful products are created. Cellulose ---> glucose ---> ethanol (can be used as fuel) ---> ethylene (used as monomer in plastics)
- Problems include land clearing, and inefficiencyof acid hydrolysis (cellulose ---> glucose)
- Advantages include it is renewable resource.
Summing up, at present it is not viable due to alternatives, but there is a future for it, such as a replacement fuel.

23b:
Average titre = 18.1
Ba(OH)2 + 2HNO3 ---> Ba(NO3) + 2H2O
moles (Ba(OH)2) = 0.12 * 25/1000
= 0.003 moles
moles (HNO3) = 0.006 moles
conc. (HNO3) = 0.006/0.0181
= 0.33 mol/L

 

[ben7]

Thanks alot.
Must admit 2003 HSC is alot more cronic than 2002 and 2001. :S hope they arnt setting a trend.

 

[ben7]

Just one more Q is u can squeeze in a min to answer it. Q26 and just the answer to Q27a, dont worry bout the wroking out.
Thanks for your effort.
Ben

 

[Paroissien]

Just one more Q is u can squeeze in a min to answer it. Q26 and just the answer to Q27a, dont worry bout the wroking out.
Thanks for your effort.
Ben

26:
- Eutrophication results from high nutrients levels, often caused by phosphates and nitrates from fertilisers.
- Causes algal blooms which used DO and chokes the water
- Can be monitored directly by measuring levels of phosphate (max 60ppm) and nitrogen (max 600ppm)
- However, N ratio is a less reliable indicator (I'm not sure why this I, it is just something I read. It says this ratio cannot be used in isolation, but I don't really understand that)
- DO and BOD easier to measure therefore more suitable as indicators.

27: 74%

 

[ben7]

Hey thanks!
I shouldnt have said just one more, you probly think this guys kidding if he wants more, but mate if you have time im stuck in the industrial chem option. (c) and (d)iii.
Thanks alot! just think its like revison writing it out again
Ben

 

[Paroissien]

Sorry mate, I don't do Industrial Chem, so I can't help you there

 

[ben7]

No worries! You have been very very helpful today, thanku.

Calling industrial chem people, just an outline for an answer for Q30(c), (d)iii and (e). I dont actually remember learning to analyse how structure led to change. Soap..grr.

Ben

 

[ashtor]

They found out that the cleaning action of soaps was seriously hindered by hard water due to scum formation...so synthetics that were much better in hard water were developed. However, due to their branched chain structure they weren't biodegradable and so formed foam in rivers etc..So furhter reserach made straighter chain anionics that could be broken down by bacteria into CO2 and H2O. Further reserach led to the development of cationics and anionics for different purposes and these wre completely unaffeceted by hard water (unlike anionics that tied up), but cationics were found to have biocidal properties.
I cant b bothered thinkin now for d)ii, but WTF is e on about??

 

[ben7]

thanks a heap, ill put it up in the industrial chem section with the other Qs.

 

[ben7]

I need another answer please from the paper if anyone has time. Q17 (b). I have seen all sorts of different info on this in text books, a condensed exam answer would be nice thanks to anyone with the answers.

Ben

 

[Paroissien]

The process is polymerisation forming polyethylene from ethylene monomers. Ethylene is changed from a gas to a liquid under pressure and heated in the presence of a catalyst to produce polyethylene.
The double bond within ethylene is broken and a covalent bond forms between monomers resulting in a long chain; addition polymerisation

 

[ben7]

Thank-you but i was looking at makring guidlines and it says this for all 3 marks:

Provides a thorough description of the three key steps in free radical
addition polymerisation or the steps in Ziegler/Natta polymerisation

I was wondering about that.. is that your answer or from the success one book?

 

[Paroissien]

That's Success One.
Well the free radical addition polymerisation forms LDPE and Ziegler/Natta forms HDPE.
For production of LDPE:
The ethylene is heated under very high pressure in the presence of an organic peroxide catalyst. The catalyst acts as the initiator by the reacting with the ethylene doulble bond producing a free radical, which of course combines with other free radicals to produce a chain, which of course is LDPE.

I think Success One's answer is enough

EDIT: It just clicked that the three steps they are talking about are initiation, propagation and termination, which cannot be accurately controlled resulting in random chain lengths, which relates back to your earlier question

Wow my spelling is awesome

 

[ben7]

Your a legend, why text books and teachers (well my teacher) dont put it simple like that i dont know.

THanks again.
Ben