criticise my syllabus summary! (1 Viewer)

[brightsea]

Ben, I only did a quick skim but it looks like you've got some good info.

One of the dot points I change though would be

 Explain what is meant by a condensation polymer

Condensation polymers are polymers created by the process of condensation polymerisation.

Since the dot point says "Explain" (Def: Relate cause and effect; make the relationships between things evident; provide why and/or how) it calls for a little more detail. Maybe something a bit more like this: A condensation polymer is a substance/molecule which has been formed when monomer units join together by a reaction which eliminates a small molecule (often water).

Also, (and this is just a personal preference when studying) I'd make your notes into dot point summaries.

Identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum

Fractional distillation = process where hydrocarbons separated through diff b. pts

2 fractions (naptha + LPG [liquefied petroleum gas]) used to manufacture C2H4 ethylene (ethene)

General term to produce ethylene = cracking.

Cracking = long chain hydrocarbon breakdown (C15-100) into shorter/useful hydrocarbons.

Cracking = 2 types

Thermal cracking
High temperatures (450-750 oC) + pressures (up to 70 atm) w/o catalyst
Products obtained = mainly unsaturated hydrocarbons – because C-C bonds break = free radical formation --> various products
(Therefore symbol) thermal cracking favoured over catalytic

Catalytic cracking
Low temperatures (approx 500oC) + low pressures
Zeolite (sodium aluminosilicate) catalyst used = lowers reaction activation energy (therefore) lower temps/pressures.
(Therefore) catalytic cracking = more energy friendly process than thermal

It's just a suggestion, from experience. If you don't want to do it for these notes perhaps do it when the HSC is closer, for revision.

 

[pLuvia]

Condensation polymerisation involves a reaction between two different monomer units (sometimes called copolymers) where each monomer has two identical functional groups. The formation of a polymer chain occurs when the two functional groups of the monomer units join and a small molecule; in this case water is ejected. Repetition of this mechanism ensures long and linear polymer chains. Examples are given below.

This reaction is the dehydration reaction which removes water molecules from a compound.
You add this bit here

 

[iyamahobbit]

 Identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum

Fractional distillation is a process by which hydrocarbons are separated through different boiling points into fractions. Two fractions in particular, known as the naptha and LPG (liquefied petroleum gas), are used to manufacture C2H4 ethylene (ethene).

The general term for the process used to produce ethylene is cracking. Cracking is the breakdown of longer chain (C15-100) hydrocarbons into shorter and more useful hydrocarbons. There are two types of cracking, thermal (steam) and catalytic cracking.

Thermal cracking involves high temperatures (450oC to 750 oC) and pressures (up to 70 atmospheres) without the presence of a catalyst. Products obtained from this process are mainly unsaturated hydrocarbons – this is because the carbon-carbon bonds break resulting in the formation of free radicals leading to various products. For this reason, thermal cracking is favoured over catalytic cracking.

Catalytic cracking, on the other hand, uses low temperatures (approximately 500oC) and low pressures with a zeolite (sodium aluminosilicate) catalyst which lower the activation energy required for reactions to take place hence the lower temperatures and pressures. Because of this, catalytic cracking is a more energy friendly process than thermal cracking.

Just a note for general note-making strategy - don't go over the top making notes from books - some of the books were written to the old chem syllabus that had 25% more info, so just cos it's in the textbook doesn't mean you need to know it.

For this dot point, remember that it only says -

 Identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum

As a rule for how much u need to know, when it says "identify", more often than not, all you need to know is actually in the dot point itself.

I can't remember if the syllabus talks about it elsewhere, but for that dot point you definately don't need to distinguish between thermal and chemical cracking. Might be worth a read, but don't waste ur time learning it.

 

[Monstar]

Hye guys, the notes in my book are a bit blank about this dot point:

"Describe the addition of water to ethylene results in the production of the ethanol and identity the need for a catalyst in the process and the catalyst used."

 

[pLuvia]

The additional reaction is hydration which is the addition of water molecules to a compound.
The catalyst used is usually dilute aqueous sulfuric acid and heat is usually needed as well.

CH₂=CH₂ + H₂O ------> CH₃-CH₂-O-H

-------> dilute sulfuric acid

Here water molecules are added to the ethene which produces ethanol.

NOTE: Dehydration and hydration can be applied to any alkane and alene respectively

Hope this helped

 

[Monstar]

^^ thats exactly what i had for the last dot point

 

[pLuvia]

Is that a good thing? Or did you just want reassurance?

 

[Monstar]

Well it didnt really say anything about the NEED for a catalyst.

mmm Well i know what a catalyst is for, so should i just put that down?

 

[Dreamerish*~]

Well it didnt really say anything about the NEED for a catalyst.

mmm Well i know what a catalyst is for, so should i just put that down?

Yes, it does say "identify the need", but since everyone has such high expectations of short-answer questions, markers will be forced to be picky.

If it was something really difficult to remember, then I'd say forget it, but since it's just a couple of words on the side, it's probably best to put it in. So you would identify the need of the catalyst, and also name it.

 

[xvelidras]

Well it didnt really say anything about the NEED for a catalyst.

mmm Well i know what a catalyst is for, so should i just put that down?

Technically speaking, the catalyst in hydration of ethene is the H+ in the acid. Hence industrially, the use of dilute phosphoric acid, and in the laboratory, dilute sulfuric acid. H+ is required because ethene and water will not readily attack each other, and hence will NOT react to form ethanol. H+ however, acts as an electrophile (electron loving species) and will attack the double bond of ethene. Reactions to complete the hydration of ethene then occur. They will not minus that initial step with the catalyst

Of course, you dont have to learn/write that mouthful. You can utilise what you know about catalysts and APPLY it to this reaction.
-ethene and water will not readily react with each other
-hence, H+ provides the alternative pathway for the reaction to proceed

 

[Riviet]

-identify the need for a catalyst...

All you need to say for this part of the dot point is "A dilute sulfuric acid catalyst is used to lower the activation energy for the reaction to proceed." Nice and concise. Even answers the next bit of the dot point too.

 

[.ben]

Does anyone know what to write for the production of transuranic elements and teh difference between that and the production of commerical isotopes?

btw thanks for all the input guys i will post another edited one in a few days.

 

[Dreamerish*~]

Does anyone know what to write for the production of transuranic elements and teh difference between that and the production of commerical isotopes?

btw thanks for all the input guys i will post another edited one in a few days.

By definition, transuranic elements are those with an atomic number higher than that of uranium (92).

Commercial radioisotopes are those that serve a purpose other than sit there and emit radiation.

Both transuranic and commercial radioisotopes can be made by:

• Bombarding with neutrons in a nuclear reactor
• Bombarding with high speed positive particles in a linear accelerator or a cyclotron

The difference between the two would be that when making commercial radioisotopes, there is a known target. For exmaple, we know that to make cobalt-60, cobalt-59 needs to be bombarded with a neutron. So what we'll do is just that.

Transuranic radioisotopes, on the other hand, is something like whacking a neutron or positron into a nuclei and seeing what you get from it. Also note that not all transuranic radioisotopes have commercial use, and that not all commercial radioisotopes are transuranic.

 

[pLuvia]

Just out of interest .ben, what textbook you use for school?

 

[beabenn]

Does anyone know what to write for the production of transuranic elements and teh difference between that and the production of commerical isotopes?

btw thanks for all the input guys i will post another edited one in a few days.

Basically, what Dreamerish posted is spot on but she's missing one thing:
a chemical equation
so you would use this equation in your answer as a supporting examplke and to illustrate that you have a firm knowledge of the topic.
So cobalt-59 + neutron = cobalt-60
Very simple of course use element notation where Co represents cobalt and "n" represents a neutron also use subscript and superscript to show atomic numbers and atomic weights.
This is very noitty-gritty but often an equation is worth AT LEAST ONE MARK

 

[Dreamerish*~]

Basically, what Dreamerish posted is spot on but she's missing one thing:
a chemical equation
so you would use this equation in your answer as a supporting examplke and to illustrate that you have a firm knowledge of the topic.
So cobalt-59 + neutron = cobalt-60
Very simple of course use element notation where Co represents cobalt and "n" represents a neutron also use subscript and superscript to show atomic numbers and atomic weights.
This is very noitty-gritty but often an equation is worth AT LEAST ONE MARK

Absolutely.

I forgot to add that in all short-answer questions, write equations and draw diagrams or flowcharts to clarify your answer.

Pluvia - I think Ben would be using Chemistry Contexts and Chemistry Pathways. I assume our school's not dumping our new Contexts after just one year. They've got something against Conquering, but we know everyone secretly uses it at home.

 

[.ben]

yes, i will add the equations into the examples thansk for reminding me.

yeh at school we use chemistry contexts and they gave us chemistry pathways. we're probably not gonna dump context cos it looks so new! but that aside ms eastment's got a stack of good bio/chem/phys/maths books for us to borrow!

Just one more question tho, do we need to know about half life and its calculations?

thanks you guys you've been of great help!

 

[Dreamerish*~]

yes, i will add the equations into the examples thansk for reminding me.

yeh at school we use chemistry contexts and they gave us chemistry pathways. we're probably not gonna dump context cos it looks so new! but that aside ms eastment's got a stack of good bio/chem/phys/maths books for us to borrow!

Just one more question tho, do we need to know about half life and its calculations?

thanks you guys you've been of great help!

You need to know what half life is and what it means. I don't recall any calculations concerning half-life, so probably not.

 

[pLuvia]

Well you should already know about it, but it's not in the syllabus

 

[.ben]

ok fantastic. certainly saves a lot of work!

thanks!