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Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: lulu10 on June 05, 2010, 09:01:35 am

Title: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: lulu10 on June 05, 2010, 09:01:35 am
GUYS,
im going absolutely crazy :|.

How do you kno when the electrolyte is molten, aqeous or dilute.

EXAMPLE: JUNE'09 Q2.  :-[ :-[ :-[ :-[ :-[ :-[
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Adham-amr on June 05, 2010, 09:49:23 am
if the electrolyte is molten it's used up e.g molten lead bromide Pb+ at cathode and Br- at anode
if aqueous or dilute they're both the same they have the same but extra two ions
e.g aqueous or dilute sodium chloride they have Na+ Cl- and H+ OH- from water
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: princess12 on June 05, 2010, 09:51:17 am
can any 1 tell me the structure of but-2-ene
reply me  ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( :'(
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: mohit1234 on June 05, 2010, 10:02:19 am
here is a pic
sorry fr the bad drawing :P
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Liya on June 05, 2010, 12:17:45 pm
here is a pic
sorry fr the bad drawing :P

how about poly - but-2-ene ?
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Ivo on June 05, 2010, 12:21:39 pm
how about poly - but-2-ene ?

Sorry for my appalling drawing!  :D
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: username on June 05, 2010, 12:23:34 pm
Sorry for my appalling drawing!  :D
hey
wont polybut-2-ene
hav the same structure as polybutene
???
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Ivo on June 05, 2010, 12:25:48 pm
hey
wont polybut-2-ene
hav the same structure as polybutene
???

Nah, it would be slightly different.  This is poly(but-1-ene).
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: username on June 05, 2010, 12:28:09 pm
Nah, it would be slightly different.  This is poly(but-1-ene).
whoa
how can u make the diffrence???
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Ivo on June 05, 2010, 12:31:29 pm
whoa
how can u make the diffrence???

Because the double bond in the monomer of but-1-ene and but-2-ene is different, so obviously the monomers for them are slightly different.
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Liya on June 05, 2010, 12:48:11 pm
can someone list the name of those -ene?
if i'm not wrong, it depends on how many carbon(s) did they have, doesn't it?

and what are the difference between alkene(methene,buthene,etc), alkane (methane,buthane,etc), alcohol (methanol, etc), and others (i forget the rest)?
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: mohit1234 on June 05, 2010, 01:16:41 pm
can someone list the name of those -ene?
if i'm not wrong, it depends on how many carbon(s) did they have, doesn't it?

and what are the difference between alkene(methene,buthene,etc), alkane (methane,buthane,etc), alcohol (methanol, etc), and others (i forget the rest)?

ethene    C2H4
propene    C3H6
butene    C4H8
pentene  C5H10
Hexene   C6H12
Septene  C7H14
Octene   C8H16

theres no methene cos CH2 cannot exist

alkenes have a double bond
alkanes dont hve a double bond

Alkanes formula - CnH2n+2
Alkenes formula - CnH2n
Alcohols formula - CnH2n+1OH
Carboxylic Acids formula - CnH2n+1COOH

Anything else??
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Liya on June 05, 2010, 01:26:49 pm
thank you!! :D
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Helium on June 05, 2010, 04:09:04 pm
NEVER MIND
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: mohit1234 on June 05, 2010, 04:11:03 pm
No one answered lulu's question.

I'll look into it :D



i think someone did
look here

if the electrolyte is molten it's used up e.g molten lead bromide Pb+ at cathode and Br- at anode
if aqueous or dilute they're both the same they have the same but extra two ions
e.g aqueous or dilute sodium chloride they have Na+ Cl- and H+ OH- from water
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: Helium on June 05, 2010, 04:12:26 pm
i think someone did
look here


LOL looks like i'm blind :-[
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: mohit1234 on June 05, 2010, 04:14:39 pm
LOL looks like i'm blind :-[

dont worry it happens sometimes :)
its happened to me also sometimes, i just look again b4 i post ;)
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: J.Darren on June 05, 2010, 06:30:19 pm
ethene    C2H4
propene    C3H6
butene    C4H8
pentene  C5H10
Hexene   C6H12
Septene  C7H14
Octene   C8H16

theres no methene cos CH2 cannot exist

alkenes have a double bond
alkanes dont hve a double bond

Alkanes formula - CnH2n+2
Alkenes formula - CnH2n
Alcohols formula - CnH2n+1OH
Carboxylic Acids formula - CnH2n+1COOH

Anything else??
Esters.

Single bond - saturated
Double bond - unsaturated

Alkenes - Test : Bromine water would turn from brown to colourless when added to alkenes.
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: NeoMarmar on June 05, 2010, 06:36:38 pm
Test for alcohols (please tell me if I'm wrong) - add alcohol to acidified potassium dichromate (VI) and warm in water bath. The solution turns green if it's positive.
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: soulreapr_ninja on June 06, 2010, 01:00:00 pm
June 2009 question # 5(b) How do i find the formual of the T phosphate thingy?? ??? :-\
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: mohit1234 on June 06, 2010, 01:46:59 pm
ive answered it here

https://studentforums.biz/index.php/topic,1411.msg249826.html#msg249826
Title: Re: Chemistry'10 paper 3. PLEASE HELP IF YOU CAN :-[
Post by: lulu10 on June 07, 2010, 09:15:58 am
guys, i've done A LOT of papers and this is what seems to come up most:

-Contact process
-harber process
- extraction of metals
- Electroylsis
-uses of sulfur dioxide
-how sulfur trioxide is formed
- fertilisers
- moles!
- how do u make sulfuric acid from SO3
-AIR + WATER!
-thermal decomposition (remember ONLY Group I metal nitartes decompose to give metal nitrite and oxygen gas)



anyone want to add to that?
feel free to. ::)