Predictions for Chemistry 2014 HSC? (6 Viewers)

Joined
Feb 16, 2014
Messages
2,258
Gender
Male
HSC
2014
Renewable: Fermentation of glucose from crops
Non-renewable: Hydration of ethylene obtained from petroleum fractions or cracking

Quick question back @ you, how come you specifically mentioned catalytic cracking? :S Isn't ethylene also from thermal
I was going to write cracking only, then my hand by accident wrote catalytic cracking, and i wasn't bothered deleting it, nor was i bothered putting thermal cracking.

Yes HSC LIFE IS GAY AND MAKES PEOPLE TIRED WHEN THEY GO AT IT FOR HOURS hahaahahah

I wouldn't personally, this question already asks for so much for only three marks.

Edit: actually yeah I would. It says from non-renewable resources in particular so I'd give a quick sentence to that and move on.
Yeah because for 3 marks, it wouldnt be enough to just say hydration and then chuck in an equation, marker would probably be like "are you a dropkick?"

yay thankss! :)
Rep worthy :p
 

enigma_1

~~~~ Miss Cricket ~~~~
Joined
Feb 27, 2013
Messages
4,281
Location
Lords
Gender
Female
HSC
2014
Yeahh brah i tried repping but it says I have to spread first. WIll do it when I can though :)
 

SuchSmallHands

Well-Known Member
Joined
Nov 13, 2012
Messages
1,391
Gender
Female
HSC
2014
Yeah because for 3 marks, it wouldnt be enough to just say hydration and then chuck in an equation, marker would probably be like "are you a dropkick?"
Obviously, but you also need to address production from non-renewable resources. So you wouldn't spend long talking about distillation and cracking. Something along the lines of 'ethanol can be produced by the hydration of ethene using diluted H2SO4 as a hydrating agent: C2H4 + H20<---(dilute H2SO4)---> CH2CH3OH. Ethene, in turn, can be produced from the fractional distillation of petroleum or the cracking of less useful fractions of petroleum. Thermal cracking (occurs at 700-100 degrees Celsius) or catalytic cracking (occurs at around 500 degrees Celsius in the presence of an aluminosilicate zeolite catalyst) may be used to decompose a longer hydrocarbon chain into a smaller alkane and alkene (eg. ethene) C12H26 ---> C10H22 + C2H4.' is probably more than sufficient for 1.5 marks. I'm actually a little pissed off I had to write that much to get 1.5 marks worth of content in. Someone else could probably do it more succinctly than that.
 
Joined
Feb 16, 2014
Messages
2,258
Gender
Male
HSC
2014
Obviously, but you also need to address production from non-renewable resources. So you wouldn't spend long talking about distillation and cracking. Something along the lines of 'ethanol can be produced by the hydration of ethene using diluted H2SO4 as a hydrating agent: C2H4 + H20<---(dilute H2SO4)---> CH2CH3OH. Ethene, in turn, can be produced from the fractional distillation of petroleum or the cracking of less useful fractions of petroleum. Thermal cracking (occurs at 700-100 degrees Celsius) or catalytic cracking (occurs at around 500 degrees Celsius in the presence of an aluminosilicate zeolite catalyst) may be used to decompose a longer hydrocarbon chain into a smaller alkane and alkene (eg. ethene) C12H26 ---> C10H22 + C2H4.' is probably more than sufficient for 1.5 marks. I'm actually a little pissed off I had to write that much to get 1.5 marks worth of content in. Someone else could probably do it more succinctly than that.
Through non-renewable resources, ethylene is first formed through catalytic cracking where large alkane molecules with 15-25 carbon atoms are split into two smaller molecules, one ethylene and the other another alkane. OR ethylene can be produced through thermal cracking where alkanes are mixed with steam and passed through hot metal coils forming ethylene. Ethylene is then hydrated, forming ethanol. Insert Equation.Ethanol from renewable resources, firstly glucose is extracted from cellulose in sugar cane or corn plants. Suspension cellulose containing materials are heated moderately with concentrated (4M) sulfuric acid breaking down the cellulose into glucose. The insoluble matter, particularly lignin from woodpulp is then filtered off. Other impurities are removed through fractional distillation and acid neutralised, forming a pure solution of glucose. Glucose is then fermented (yeast cells, anerobic respiration at 35 degrees) forming carbon dioxide and ethanol. Insert equation.

For 3 marks, i think what i've written is overkill but at the same time, it explains everything that's is supposed to be there and is most likely in the marking criteria. I really dislike the fact that straightforward questions require all this extra info to allow the marker know what you're on about.
 

QZP

Well-Known Member
Joined
Oct 7, 2013
Messages
839
Gender
Undisclosed
HSC
2014
We should do more questions relating to dotpoints where students often forego e.g.
- outline the role of a chemist employed in a named industry or enterprise, identifying the branch of chemistry undertaken by the chemist and explaining a chemical principle that the chemist uses
- identify the need for collaboration between chemists as they collect and analyse data

Anyone have any past HSC/trial paper questions on these!?? IM REALLY SCARED :(

Also, what's the difference between the first dotpoint mentioned above with this:
- gather, process and present information from secondary sources about the work of practising scientists identifying: the variety of chemical occupations, a specific chemical occupation for a more detailed study
 

enigma_1

~~~~ Miss Cricket ~~~~
Joined
Feb 27, 2013
Messages
4,281
Location
Lords
Gender
Female
HSC
2014
It was over pm, he messages me asking for advice, and obviously i was not going to lie and tell him to do 4u because he sucks at 3u, and he gets pissed off hahahaha


It was over pm not in the threads
lol
tell him truth hurts
 

SuchSmallHands

Well-Known Member
Joined
Nov 13, 2012
Messages
1,391
Gender
Female
HSC
2014
Through non-renewable resources, ethylene is first formed through catalytic cracking where large alkane molecules with 15-25 carbon atoms are split into two smaller molecules, one ethylene and the other another alkane. OR ethylene can be produced through thermal cracking where alkanes are mixed with steam and passed through hot metal coils forming ethylene. Ethylene is then hydrated, forming ethanol. Insert Equation.Ethanol from renewable resources, firstly glucose is extracted from cellulose in sugar cane or corn plants. Suspension cellulose containing materials are heated moderately with concentrated (4M) sulfuric acid breaking down the cellulose into glucose. The insoluble matter, particularly lignin from woodpulp is then filtered off. Other impurities are removed through fractional distillation and acid neutralised, forming a pure solution of glucose. Glucose is then fermented (yeast cells, anerobic respiration at 35 degrees) forming carbon dioxide and ethanol. Insert equation.

For 3 marks, i think what i've written is overkill but at the same time, it explains everything that's is supposed to be there and is most likely in the marking criteria. I really dislike the fact that straightforward questions require all this extra info to allow the marker know what you're on about.
Because of the 'state any reaction conditions required' I'd say you'd need to list the temperature required for thermal and catalytic cracking and the catalyst required for catalytic, I would anyway just to cover myself (some marking criteria are bitchy as hell).
 
Joined
Feb 16, 2014
Messages
2,258
Gender
Male
HSC
2014
We should do more questions relating to dotpoints where students often forego e.g.
- outline the role of a chemist employed in a named industry or enterprise, identifying the branch of chemistry undertaken by the chemist and explaining a chemical principle that the chemist uses
- identify the need for collaboration between chemists as they collect and analyse data

Anyone have any past HSC/trial paper questions on these!?? IM REALLY SCARED :(

Also, what's the difference between the first dotpoint mentioned above with this:
- gather, process and present information from secondary sources about the work of practising scientists identifying: the variety of chemical occupations, a specific chemical occupation for a more detailed study
I'm not sure, they seem very similar.

Anyways to answer first dot point.

John Smith is an analytical chemist who works in the Haber industry monitoring the contents of the reaction vessel. The chemical principle that he employs is that of solubility where he uses gas liquid chromatography to monitor the contents of the gas as it is passed over a liquid stationary phase. John Smith, being an analytical chemist must ensure that the ratio of nitrogen to hydrogen is 1 to 3 to ensure maximum efficiency as well as yield production, and must constantly monitor the vessel and ensure that there is no carbon monoxide or sulfur as it poisons the catalyst magnetite, and thus halting the process as the catalyst has to be replaced and as a result reducing efficiency and yield production.
 

seventhroot

gg no re
Joined
Aug 3, 2014
Messages
2,803
Gender
Male
HSC
2013
It was over pm, he messages me asking for advice, and obviously i was not going to lie and tell him to do 4u because he sucks at 3u, and he gets pissed off hahahaha

It was over pm not in the threads
lel I get the same things; people are like "can I do engineering with general maths" or "what is mech like" and I tell them gg no re then they go on a rant lol;

tbh; don't PM me about that stuff; make a thread and I will reply of you're srs otherwise so everyone can see the help
 

Users Who Are Viewing This Thread (Users: 0, Guests: 6)

Top