Cssa Trials... (1 Viewer)

[velox]

lol oh how we do think alike... evertime i'd come to write something.. the word 'ethanol' would click in my head

i spoke about it being a condensation polymer, monomer being glucose.. blah blah blah blah blah.... hang on condenstaion or addition.....

no i think it's condenstaion?.... help!!! no wait it is.. isn't it???

Cellulose is a condensation biopolymer formed by glucose monomers. It is a long, flat and rigid molecule, up to 10000 glucose units long. During condensation polymerisation, water is condensed and β-glucose monomers are linked by an ether functional group (commonly called a β-1,4-glycosidic bond) to form a β-maltose dimer.

Cellulose is a major component of biomass. Biomass is mainly carbonaceous matter derived from the photosynthetic activity of plants, thus it is renewable.

 

[~ ReNcH ~]

actually the test was ok, but i thought the multiple choice was gay

for the NaHCO3 question i got 1495.(something)gram. i think because i used all the decimals for atomic weight to calc, but i dun know...can someone verify?

what did people get for the molar heat of combustion question, as i got 1391 something, but i dun know how i got it....

also the last question of MC what did u get? how do you do that question? a right answer would be appreciated....and for the oyster, was it 6 oysters?

I got 371 or 3xx anyway for the molar heat of combustion of ethanol.

 

[Numero Uno]

Wtf I Just Finished my exam at 4: 30 pm
Darren should have gave me the answers !!

 

[velox]

Yep, its condensation

And ummm, with that pH of HCl question.
I put pH one.
My reasoning is that despite the HCl being diluted, pH isnt like moles or Molarity, therefore, how can it change?
I thought that the pH of a substance was always constant no matter wat happens to it.... :S

Yeh and HCl is a strong acid thus it is fully ionised.

 

[~ ReNcH ~]

there is?? its about like why is cellulose more viable than carbon compounds

Wasn't the question along the lines of...assess the viability of cellulose as a substitute for petroleum. I said:
For: renewable
Against: more expensive to harvest, requires larger areas of land
Final conclusion: not suitable at this point in time...until a more efficient method of producing cellulose is found.

 

[Numero Uno]

Whats this MC crap

Our school changed around 3 sections and added totally random questions

 

[physician]

I got 371 or 3xx anyway for the molar heat of combustion of ethanol.

yeh i think i got something like..
we were supposed to calculate it per gram first then per mole right?

 

[queenie]

Easiest test in history. Though the oyster was actually impossible as they didn’t give you the weight of the average oyster.

dude, who cares about the weight of the oyster? it was dealing about the mass of zinc or whatever. IT WAS possible - you didn't need the weight of any oyster.


And guys, for the ph question, i used C1V1=C2V2

Ie, the concentration to begin with was 0.1 and the volume was 0.1 and the volume to end with was one litre... so you get the concentration, then neg log it, and u get 2.

Thats what i did anyway.

 

[richz]

duno forgot, cuz it was a tedious q anyway for the ethanol heat of combustion i got 300KJ/mol or so too

 

[~ ReNcH ~]

Wtf I Just Finished my exam at 4: 30 pm
Darren should have gave me the answers !!

lol...I finished at 4:15. Only fifteen minutes - not enough time for answer exchanging

 

[velox]

Wasn't the question along the lines of...assess the viability of cellulose as a substitute for petroleum. I said:
For: renewable
Against: more expensive to harvest, requires larger areas of land
Final conclusion: not suitable at this point in time...until a more efficient method of producing cellulose is found.

haha identical to success one. Just did that question today.

 

[~ ReNcH ~]

dude, who cares about the weight of the oyster? it was dealing about the mass of zinc or whatever. IT WAS possible - you didn't need the weight of any oyster.


And guys, for the ph question, i used C1V1=C2V2

Ie, the concentration to begin with was 0.1 and the volume was 0.1 and the volume to end with was one litre... so you get the concentration, then neg log it, and u get 2.

Thats what i did anyway.

So what was your answer to the oyster question (+ your reasoning)?

 

[~ ReNcH ~]

haha identical to success one. Just did that question today.

Was my answer wsimilar to the answer given? (I don't have the SuccessOne book). You would expect similar questions to arise, since they're working from the one limited syllabus.

 

[queenie]

i cant remember what my answer was, but it was pretty small. I think 1.6 or 6? *shrugs* i can do it again if you give me the question... i cant remember.

 

[velox]

Yep thats it.

The long chain carbon structure of cellulose gives it the potential to replace petroleum as the feedstock for petrochemicals. The conversion of long chains of cellulose into glucose monomers by acid hydrolysis or by enzymes, though currently possible, is not economically viable.

Rench, i think you should have also mentioned the complicated and expensive conversion process of long chains of cellulose into glucose monomers by acid hydrolysis or by enzymes.

 

[queenie]

what did pple say for that sulfate/fertiliser question?

Why the hell did he put more ba into the filtrate?

i THINK i said to check that all the sulfate had gone or something.. A

 

[velox]

omg they always test something about that. I cant even remember that prac.

 

[queenie]

lol nah i could remember the prac, but the weirdo in the exam decided to do some method i had never done before. So yay for him. Stupid twit.

 

[Pointy Ears]

what did pple say for that sulfate/fertiliser question?

Why the hell did he put more ba into the filtrate?

i THINK i said to check that all the sulfate had gone or something.. A

Ummm, yep, thats it.
Apparently, ur supposed to add more Ba after the initial titration to check for more precipitates. Weird, my school didnt actualy do that, i got it from the papers...

 

[~ ReNcH ~]

Yep thats it.

The long chain carbon structure of cellulose gives it the potential to replace petroleum as the feedstock for petrochemicals. The conversion of long chains of cellulose into glucose monomers by acid hydrolysis or by enzymes, though currently possible, is not economically viable.

Rench, i think you should have also mentioned the complicated and expensive conversion process of long chains of cellulose into glucose monomers by acid hydrolysis or by enzymes.

True, though I hope that the criteria doesn't necessitate that that be included. I had no idea about the processes actually used to break down cellulose so it's evidently an area I need to revise