HSC 2017 Chemistry Marathon (1 Viewer)

[eyeseeyou]

Welcome to the HSC chemistry marathon

This thread is an open chain of questions between students. It works by answering a question then posting another question and allowing the cycle to repeat itself as this is used to test others!

Just some simple rules:
- Answer the question asked previously, before posting a new question.
- After you have answered a question, post another question to keep the thread alive (or else I have to come in and post a new question)
- try to allocate a number of marks for any question that you post.

Tips:
- It may help to write your answers on paper before typing them on this thread as it will mirror your exam.
- You may post more than one question.
- When possible, after questions have been answered, you can peer mark using the marking scheme.

Source: http://community.boredofstudies.org/17/chemistry/344627/hsc-chemistry-marathon-2016-a.html

I will start off:
Write an equation for the fermentation of glucose and describe the optimal conditions under which fermentation is promoted (3 marks)

For future reference, please refrain from using this thread for help. Instead I'd suggest you make your own individual thread in the Chemistry Section of this forum if you want help

Also, please refrain from derailing this thread. If you want to talk about a specific topic or whatever to someone else, please do it via PM or have the conversation somewhere else as we want the marathon running smoothly

 

[Snowflek]

Re: HSC Chemistry Marathon 2017

May someone help me with this question and explain it thoroughly to me? Thank you
1. Explain how the structure and properties of polyethylene and poly(vinylchloride) relate to the way each is used.
2. The structure of a commercially significant monomer is shown below. (Sorry im going to have to explain it since i need to identify the name of this monomer and can't just search it up and post a picture)
The strucutre is H2C=CH- hexagonal shape attached to the single bond of CH
a) Identify the common name of the monomer.
B) the uses of polymers are dependent on their properties. Discuss this statement with reference to a polymer made from one of the above monomers.

 

[Snowflek]

Re: HSC Chemistry Marathon 2017

May someone help me with this question and explain it thoroughly to me? Thank you
1. Explain how the structure and properties of polyethylene and poly(vinylchloride) relate to the way each is used.
2. The structure of a commercially significant monomer is shown below. (Sorry im going to have to explain it since i need to identify the name of this monomer and can't just search it up and post a picture)
The strucutre is H2C=CH- hexagonal shape attached to the single bond of CH
a) Identify the common name of the monomer.
B) the uses of polymers are dependent on their properties. Discuss this statement with reference to a polymer made from one of the above monomers.

For the 2nd question, i think its styrene but i just dont understand what the hexagonal shape there is for? Like what is it

 

[Fizzy_Cyst]

Re: HSC Chemistry Marathon 2017

[HR][/HR]

For the 2nd question, i think its styrene but i just dont understand what the hexagonal shape there is for? Like what is it

It's a phenyl group. C6H5

It is NOT Benzene. It is Benzene minus a hydrogen.

 

[Snowflek]

Re: HSC Chemistry Marathon 2017

https://www.google.com.au/search?es...mg..4.3.652.WyEtaaenIP0#imgrc=fxCQT4Yl-fiRgM:
Yeah this is it. Same structure. But what on earth is with this benzene like i dont get it. I just finished year 11 and doing some yr 12 stuff in the holiday to prepare myself so yeah. So the name is styrene i guess?

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

I will start off:
Write an equation for the fermentation of glucose and describe the optimal conditions under which fermentation is promoted (3 marks)

^

 

[Incandescence]

Re: HSC Chemistry Marathon 2017

Welcome to the HSC chemistry marathon
This thread can be used to ask for help or test others!
Just some simple rules:
- Answer the question asked previously, before posting a new question.
- After you have answered a question, post another question to keep the thread alive.

I will start off:
Write an equation for the fermentation of glucose and describe the optimal conditions under which fermentation is promoted (3 marks)

The fermentation of glucose involves the breaking down of glucose into ethanol and carbon dioxide by microbial enzyme action, especially that of yeast.
Equation:
glucose -> ethanol + carbon dioxide gas
C6H12O6 (aq) -> 2C2H5OH(aq) + 2CO2(g)
The optimal conditions under which fermentation is promoted are: the glucose being in aqueous state (may be in mashed grain or fruit form), an anaerobic environment, a temperature of approximately 37 degrees celsius, and the presence of yeast cultures which contain the enzymes required to catalyse the reaction.


Next question:
[BOS 2009 Q19]
Outline the chemical and physical processes involved in the production of ONE of the following from a natural raw material. Include relevant chemical equations in your answer. (6 marks)

- a polyethylene bottle
- a polyvinyl chloride pipe
- a polystyrene cup

 

[jazz519]

Re: HSC Chemistry Marathon 2017

The fermentation of glucose involves the breaking down of glucose into ethanol and carbon dioxide by microbial enzyme action, especially that of yeast.
Equation:
glucose -> ethanol + carbon dioxide gas
C6H12O6 (aq) -> 2C2H5OH(aq) + 2CO2(g)
The optimal conditions under which fermentation is promoted are: the glucose being in aqueous state (may be in mashed grain or fruit form), an anaerobic environment, a temperature of approximately 37 degrees, and the presence of yeast cultures which contain the enzymes required to catalyse the reaction.


Next question:
[BOS 2009 Q19]
Outline the chemical and physical processes involved in the production of ONE of the following from a natural raw material. Include relevant chemical equations in your answer. (6 marks)

- a polyethylene bottle
- a polyvinyl chloride pipe
- a polystyrene cup

 

[jazz519]

Re: HSC Chemistry Marathon 2017

Identify and Describe the chemical processes of converting large hydrocarbons in crude oil to lower molecular weight hydrocarbons such as ethene (4 marks), including relevant equations

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

Identify and Describe the chemical processes of converting large hydrocarbons in crude oil to lower molecular weight hydrocarbons such as ethene (4 marks), including relevant equations

One of the methods used to convert large hydrocarbons in crude oil to lower molecular weight hydrocarbons such as ethene is Thermal cracking where a mixture of hydrocarbons and steam is passed through heated coils where it is done typically at 750-900 degrees as the high temperatrue is needed to break the covalent bond. Furthermore there is an absence of air which prevents combustion of hydrogen and the mix of products obtained are shorrter alkanes and small alkenes.

The first step in thermal cracking is Initiation where free radicals produced when hydrocarbons are split by high temperatures. The second step is propagation where free radicals breaks into smaller radicals and produce ethene. The third step is termination where remaining free radicals react with each other to reform hydrocarbons

C10H22(g)--->C6H14(g)+2C2H4(g)

(someone plz tell me if I've done something wrong)

Question:

Discuss the need for alternative sources of the compounds presently obtained from the petrochemical industry (5 MARKS)

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

One of the methods used to convert large hydrocarbons in crude oil to lower molecular weight hydrocarbons such as ethene is Thermal cracking where a mixture of hydrocarbons and steam is passed through heated coils where it is done typically at 750-900 degrees as the high temperatrue is needed to break the covalent bond. Furthermore there is an absence of air which prevents combustion of hydrogen and the mix of products obtained are shorrter alkanes and small alkenes.

The first step in thermal cracking is Initiation where free radicals produced when hydrocarbons are split by high temperatures. The second step is propagation where free radicals breaks into smaller radicals and produce ethene. The third step is termination where remaining free radicals react with each other to reform hydrocarbons

C10H22(g)--->C6H14(g)+2C2H4(g)

(someone plz tell me if I've done something wrong)

Question:

Discuss the need for alternative sources of the compounds presently obtained from the petrochemical industry (5 MARKS)

Also do I have to explain the chemical equation I put in my response?

 

[BlueGas]

Re: HSC Chemistry Marathon 2017

Good luck everyone!

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

Good luck everyone!

What?

 

[BlueGas]

Re: HSC Chemistry Marathon 2017

What?

For the 2017 HSC

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

For the 2017 HSC

lol thanks

One of the methods used to convert large hydrocarbons in crude oil to lower molecular weight hydrocarbons such as ethene is Thermal cracking where a mixture of hydrocarbons and steam is passed through heated coils where it is done typically at 750-900 degrees as the high temperatrue is needed to break the covalent bond. Furthermore there is an absence of air which prevents combustion of hydrogen and the mix of products obtained are shorrter alkanes and small alkenes.

The first step in thermal cracking is Initiation where free radicals produced when hydrocarbons are split by high temperatures. The second step is propagation where free radicals breaks into smaller radicals and produce ethene. The third step is termination where remaining free radicals react with each other to reform hydrocarbons

C10H22(g)--->C6H14(g)+2C2H4(g)

(someone plz tell me if I've done something wrong)

Question:

Discuss the need for alternative sources of the compounds presently obtained from the petrochemical industry (5 MARKS)

I'd appreciate if someone answered this

 

[RachelGreen]

Re: HSC Chemistry Marathon 2017

lol thanks

I'd appreciate if someone answered this

There is an overwhelming need for alternative sources that are presently derived from the petrochemical industry (e.g. Currently crude oil)
- This is because crude oil is a fossil fuel, and is hence a non-renewable resource. Based on current usage stats, crude oil stocks could be used up in several decades.
- The increasing cost of crude oil is also another factor. As it becomes more scarce, prices will increase.
- current processes to product materials from crude oil are environmentally damaging and cause large emissions of greenhouse gas, which may lead to climate change
- Most petroleum-derived polymers are currently non-biodegrable, which may lead to large waste disposal problem, as well as pollution of waterways and natural ecosystems thus as a result, the use of alternative polymers derived from alternate, natural sources, biodegrable polymers can alleviate these detrimental enviromental impact
- Furthermore, alternatives are largely uneconomical currently and until they become financially feasible, it cannot effectively replace crude oil.

[NEXT QUESTION]:
Compare and contrast addition polymerisation and condensation polymerisation reactions, by providing an example for each reaction as well as comparing the monomers used. Provide diagramS. [6]

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

There is an overwhelming need for alternative sources that are presently derived from the petrochemical industry (e.g. Currently crude oil)
- This is because crude oil is a fossil fuel, and is hence a non-renewable resource. Based on current usage stats, crude oil stocks could be used up in several decades.
- The increasing cost of crude oil is also another factor. As it becomes more scarce, prices will increase.
- current processes to product materials from crude oil are environmentally damaging and cause large emissions of greenhouse gas, which may lead to climate change
- Most petroleum-derived polymers are currently non-biodegrable, which may lead to large waste disposal problem, as well as pollution of waterways and natural ecosystems thus as a result, the use of alternative polymers derived from alternate, natural sources, biodegrable polymers can alleviate these detrimental enviromental impact
- Furthermore, alternatives are largely uneconomical currently and until they become financially feasible, it cannot effectively replace crude oil.

[NEXT QUESTION]:
Compare and contrast addition polymerisation and condensation polymerisation reactions, by providing an example for each reaction as well as comparing the monomers used. Provide diagramS. [6]

The process of forming polymers is known as polymerization where there are two types: addition and condensation. Addition polymers are formed by chemically joining many monomers together without any by-product. The double bonds are broken to allow the addition of more monomers. Condensation polymers on the other hand are when polymerization occurs with many natural polymers (e.g. Cellulose, Starch, wool, silk, hair...). Condensation polymers form when monomers chemically combine by eliminating a small molecule (usually water)

I can't really be bothered providing a diagram atm soz

Question:
Describe how ONE named biopolymer is made AND explain its usefulness in term of it properties. (5 MARKS)

 

[pikachu975]

Re: HSC Chemistry Marathon 2017

http://community.boredofstudies.org...istry-hsc-extended-responses.html#post4584439

Are you just copy pasting questions from here lol

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

http://community.boredofstudies.org...istry-hsc-extended-responses.html#post4584439

Are you just copy pasting questions from here lol

Yes because coming up with questions take too long for me to think of a question and the mark allocation/marking criteria

 

[eyeseeyou]

Re: HSC Chemistry Marathon 2017

The process of forming polymers is known as polymerization where there are two types: addition and condensation. Addition polymers are formed by chemically joining many monomers together without any by-product. The double bonds are broken to allow the addition of more monomers. Condensation polymers on the other hand are when polymerization occurs with many natural polymers (e.g. Cellulose, Starch, wool, silk, hair...). Condensation polymers form when monomers chemically combine by eliminating a small molecule (usually water)

I can't really be bothered providing a diagram atm soz

Question:
Describe how ONE named biopolymer is made AND explain its usefulness in term of it properties. (5 MARKS)

BUMP