IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: thukon on May 28, 2009, 04:08:42 am

Title: Chem paper 3 help!!
Post by: thukon on May 28, 2009, 04:08:42 am: Just generally, what tests do we need to learn? Like test for sulphur dioxide other ones?

And does anyone know a chem guide website? I already know chemguide.co.uk, but thats mostly for A levels.
Title: Re: Chem paper 3 help!!
Post by: jkiam11 on May 28, 2009, 04:15:29 am: You need to know basic tests such as oxygen and hydrogen tests and also tests for soluble ions such as zinc ion and copper ions.
Title: Re: Chem paper 3 help!!
Post by: thukon on May 28, 2009, 04:17:28 am: Yes but sometimes they ask tests fro random gases like sulphur dioxide. And what catalysts do we need to know? Like for decomposition of hydrogen peroxide and what else?
Title: Re: Chem paper 3 help!!
Post by: jkiam11 on May 28, 2009, 04:25:02 am: Which paper did they ask you to test a random gas? There is nothing about identifying sulphur dioxide in the syllabus.
Title: Re: Chem paper 3 help!!
Post by: thukon on May 28, 2009, 04:47:43 am: Quote from: jkiam11 on May 28, 2009, 04:25:02 am
Which paper did they ask you to test a random gas? There is nothing about identifying sulphur dioxide in the syllabus.
Yes well theres nothing about knowing hydrogen peroxides catalyst in the syllabus either. And it came in paper 6.
Title: Re: Chem paper 3 help!!
Post by: jkiam11 on May 28, 2009, 05:00:59 am: I didn't do paper 6 so I wouldn't know but was your question abt hydrogen peroxides a suggest or deduce question?
Title: Re: Chem paper 3 help!!
Post by: chaosking on May 28, 2009, 06:14:39 am: check the syllabus
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 07:37:53 am: u gotta learn test of cations(zinc,aluminium,copper(II),calcium.iron(II),iron(III),ammonium,etc) and test of anioins(nitrates,carbonates,sulphates,chlorides,etc) and test of gasses(oxygen,hydrogen,carbon dioxide,chlorine and ammonia)
then u gotta learn how to test unsaturated hydrocarbon(with double bonds eg:ethene) where u have to use aqueous redish-brown bromine water which decolourizes when added to unsaturated hydrocarbon..

and thts all i guess
Title: Re: Chem paper 3 help!!
Post by: ~M.J~ on May 28, 2009, 07:38:17 am: TEST FOR SULPHUR DIOXIDE?
that can come
my teacher gave it in our mocks
answer??
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 07:39:55 am: @mj wat was the test for sulphur dioxide?
Title: Re: Chem paper 3 help!!
Post by: ~M.J~ on May 28, 2009, 07:41:47 am: Got it wrong in the exams! ;D
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 07:43:15 am: i dont think there was any test for so2 cuz we never came across it or maybe we did,ijust forgot
Title: Re: Chem paper 3 help!!
Post by: godfather93 on May 28, 2009, 07:45:53 am: sulphur dioxide turns acidified potassium dichromate from orange to green.
Title: Re: Chem paper 3 help!!
Post by: ~M.J~ on May 28, 2009, 07:47:08 am: Thanx 4 the answer
but may i ask in which chapter is that in!....
Title: Re: Chem paper 3 help!!
Post by: godfather93 on May 28, 2009, 07:48:42 am: Quote from: ~M.J~ on May 28, 2009, 07:47:08 am
Thanx 4 the answer
but may i ask in which chapter is that in!....
in my book it's not in a chapter but all the gas tests r given at the end of the book.
Title: Re: Chem paper 3 help!!
Post by: godfather93 on May 28, 2009, 07:50:04 am: oh yeah, it's also mentioned in the manufacture of sulphuric acid chapter.
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 07:51:08 am: OH YEA Thanks MATE tht reminded me of another test which is the test for alcohols, where u add pottasium permanganate which turns its colour from pink to colourless. and when adding pottasium dichromate where the colour turns orange to green.
@mj its in the contact process stuff wher h2so4 is made
Title: Re: Chem paper 3 help!!
Post by: godfather93 on May 28, 2009, 08:01:11 am: ur welcome. can someone please make a list of all the different processes so that it'll be easier to revise. Thanks

contact process
frasch process
ostwald process
haber's process
production of NaOH (chlor alkali industry)
production of aluminium
production of copper
production of iron (blast furnace)
extraction of zinc from zinc blende

please add on.
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 10:01:16 am: extraction and production of iron and steel
extraction of zinc blende and production of zinc
habers process
contact process
frasch process
production of copper
production of aluminuinm
production of naoh (learn the uses of chlorine and hydrogen and nacl)
ostwald process(never seen it in paper3)
soaponification
hydrolysis of protein fats and carbohydrates
formation of polymerisation especially terlyne and nylon with thoer properties and uses

i think thts all
Title: chemistry Paper 3 .. Help !!
Post by: simply.me on May 28, 2009, 10:08:19 am: hey all .. !!

can any1 help me with Pastpapers .. and useful info's for chemistry paper 3 :S
Title: Re: Chem paper 3 help!!
Post by: godfather93 on May 28, 2009, 10:08:24 am: moreover,

extraction of bromine from seawater
purification of water
extraction and separation of minerals from nodules
Title: Re: Chem paper 3 help!!
Post by: jkiam11 on May 28, 2009, 10:09:32 am: what is the frasch and ostwald process?
Title: Re: Chem paper 3 help!!
Post by: Ghost Of Highbury on May 28, 2009, 10:20:13 am: visit this site for ostwald process
http://www.digipac.ca/chemical/mtom/contents/chapter3/fritzhaber_2.htm

:)
Title: Re: Chem paper 3 help!!
Post by: Shogun on May 28, 2009, 10:41:55 am: Quote from: godfather93 on May 28, 2009, 10:08:24 am
moreover,

extraction of bromine from seawater
purification of water
extraction and separation of minerals from nodules

these u can add them for the last, cuz its truly rare to be coming on paper 3. except for purification of water.
u should aslo study electroplatig and the process of galvanising and sacraficial protection and how they all work..
Title: Re: Chem paper 3 help!!
Post by: dirtydevil on May 28, 2009, 11:02:18 am: umm i dont think dat this frasch and ostwald process is nywher in da syllabus nd we havent even taught dese processes over here so its useless..
Title: Re: Chem paper 3 help!!
Post by: Dramien on May 28, 2009, 12:26:35 pm: yea i agree to dirtydevil... theres no mention of those 2 processes in the syllabus...