Biology; Chemistry; Physics: Post your doubts here!

[Anonymous321]

Should I learn PVC, Teflon, Perspex etc? Their uses?

exactly what I'm wondering. Also their formulas

 

[Ram97]

exactly what I'm wondering. Also their formulas

Its CIE anything can come... No risks

 

[peacce]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s10_qp_22.pdf

questn A6 a ii and iii
M.s is cnfusing. can anyne pls do it for me?

 

[Laibaaa]

Should I learn PVC, Teflon, Perspex etc? Their uses?

Daafuq is that.

 

[Ram97]

Daafuq is that.

U're doomed!!
BTW That's Organic Chemistry

 

[Anonymous321]

U're doomed!!
BTW That's Organic Chemistry

Dude, they're not mentioned in the syllabus. And I skimmed through the topicals and found no questions on them.
You might wanna learn what 'polyunsaturated' means, cx its stated in the syllabus, and i have a VERY strong feeling its gonna.....cum this year.

 

[Laibaaa]

U're doomed!!
BTW That's Organic Chemistry

Where is it in the syllabus? I've done organic and this is the first i've heard of PVC, Teflon, Perspex. Where are they mentioned? :/

 

[gary221]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_qp_22.pdf

questn A6 a ii and iii
M.s is cnfusing. can anyne pls do it for me?

Okay, since the main structure has only carbon-carbon bonds, ie. no other element link N, O is involved, we can safely assume it is an addition polymer.
Monomer = repeat unit of the polymer, which is.

Since it is an addition polymer → the monomer = alkene → A C-C double bond.
So, the monomer = C6H5-CH=CH2

Hope you get it.

 

[Dark Destination]

Adv and Disadvantages of Recycling?

And what are the problems caused by disposal of plastics?

 

[Dark Destination]

Dude, they're not mentioned in the syllabus. And I skimmed through the topicals and found no questions on them.
You might wanna learn what 'polyunsaturated' means, cx its stated in the syllabus, and i have a VERY strong feeling its gonna.....cum this year.

Polyunsaturated just means a compounds with a lot of carbon-carbon double/triple bonds in a lot of places? Right?
Is this given in the book? .-.

 

[Laibaaa]

Polyunsaturate is simple lol.

There are different kind of plastics.

So now what should I learn from them?:/

 

[Anonymous321]

Polyunsaturated just means a compounds with a lot of carbon-carbon double/triple bonds in a lot of places? Right?
Is this given in the book? .-.

carbon carbon DOUBLE bonds is what it says in the marking scheme. It's given in my book, yeah.

 

[gary221]

Where is it in the syllabus? I've done organic and this is the first i've heard of PVC, Teflon, Perspex. Where are they mentioned? :/

All are addition polymers.
PVC = polyvinylchloride.
Monomer = http://www.decodedscience.com/wp-content/uploads/2012/12/PVC-formula.jpg

Teflon's monomer = http://www.pslc.ws/macrog/images/vinyl07.gif

Perspex monomer = http://3.bp.blogspot.com/-I-9a6YCgbY4/Uo1ax6SdfxI/AAAAAAAADlA/nucUe7ngIfo/s1600/Picture1m.png

Dont worry though. As long as you are thorough with your syllabus, you can answer any question..

 

[Dark Destination]

Is there an exact colour chart?

I mean - I know of the anions. Also of group 1, 2 and 7 and ammonium.

But apart Cu pink, Fe2+, Fe3+, Cu(II)O, Cu2+ I doubt I know much on colours. is there any more asked?

Colors are important for Atp.
For theory, you just need to know the common substances, the colors of precipitates and stuff.. Those are enough, i think.

 

[Dark Destination]

If you find something online. In my book, poly(ethene), poly(chloroethene) or PVC or Teflon, poly(phenylethene) or ploystrene, Perspex, poly(tetrafluroethene) or PTFE. Their uses and monomer and repeat unit and polymer are given. You can find something on google perhaps.

That's not a part of our syllabus

 

[***amd***]

Adv and Disadvantages of Recycling?

And what are the problems caused by disposal of plastics?

adv i think u can do it easily. no?
disadv:

• creation of low quality jobs
• ppl working in garbage are at risk to get fetal diseases
• new industries are to be planted for recycling; burden on economy
• cost to saperate metals from garbage is high

 

[Dark Destination]

I just did a q. where Iron displaced CU2+.

So solution turns blue ---> green with pink deposits. I am shit scared of something else coming like that AgBr in ATP.

Well, that's simple. Iron (II) solutions are green.

So saying WHITE for AgBr is wrong?

 

[***amd***]

Adv and Disadvantages of Recycling?

And what are the problems caused by disposal of plastics?

plastics are non-biodegradable i.e. they cant be decomposed. so if we deposit plastics in the earth, we are actually creating a separation between the inner and outer part of the earth by a layer of plastic. same is the case with polyethene

 

[gary221]

I just did a q. where Iron displaced CU2+.

So solution turns blue ---> green with pink deposits. I am shit scared of something else coming like that AgBr in ATP.

Iron (II) ions are green.
AgBr forms a yellow ppt. It is an insoluble salt.

 

[Dark Destination]

BTW, I wrote previously that this was a simple one. (I didn't ask for explanation). What I basically questioned was that can they give us a new ion or solid which isn't that simple? You know, something like colour of Fe, Ti etc? BTW, what are colours of grp3, 4, 5, 6 ?We need to learn those?

Honestly, you're the only one worrying about this stuff.
Even if it does come, it would only be for one mark. And this isn't even ATP.

And AgBr wasn't a heavenly thing that no one knew, it was a past paper question.
So Chill.