Chemistry Help HERE ONLY !!

[THEIGBOY]

GodFather93, THEIGBOY are on
www.drop.io/theigboy
for a group chat on anything related to IGCSE CHEMISTRY
just scroll down and open the chat menu
(chnge ur nick to correspond with studenforums)

By the way it was GodFather93's idea
Come ASAP and ask any question and we'll try our best to answer

[thukon]

Someone said most alkalis are soluble. WRONG!! All alkalis are soluble, but not all bases are soluble. Soluble bases are called alkalis.

[emi]

shogun and sweetsh ,, did u want a list of insoluble salts ??
well if you did then here is it

-all carbonates except those of group 1 metals and ammonium carbonate
-all hydroxides except those of group 1 metals and those of calcium, strontium and barium
-barium, calcium and lead sulphates
-the chlorides, bromides and iodides of both silver and lead

[evilzurg307]

Cation reactivity series:
Please-K
sent-Na
cats-Ca
monkeys-Mg
and-Al
zebras-Zn
in-Fe
large-Pb
hired-H
cages.-Cu
Make-Hg
sure-Ag
padlocked.-Pt

Thanks that helped a lot!
+rep

[emi]

can some one give me mark scheme for November 2003 paper3 ?  the one on Free exam paper is totally unrelated

ricko the one u posted was for 2005 i want 2003

[SGVaibhav]

Give
examples
of Oxidising agent and Reducing Agnet

Test for Oxidising agent

[ig_kid]

u can search for it from:
www.pastpapers4free.weebly.com
or
www.planet-master.com
 

[nid404]

can some one give me mark scheme for November 2003 paper3 ?  the one on Free exam paper is totally unrelated

ricko the one u posted was for 2005 i want 2003

here

[archangel]

@shogun

heres the list: (just the ones we need for igcse only)

                   Soluble:                                           Insoluble:
                 All nitrates

               Most Chlorides                   Except for Silver Chloride (AgCl) and Lead (II) Chloride (PbCl2)[but can be dissolved in hot water]

              Most Sulphates                   Except for Calcium Sulphate (CaSO4), Barium Sulphate (BaSO4) and Lead (II) Sulphate (PbSO4)

      Potassium Carbonate (K2CO3)                  Most Carbonates
       Sodium Carbonate (NaCO3)
    Ammonium Carbonate (NH4)2CO3

[ig_kid]

Oxidising agents:
Cl₂
Fe³⁺
Potassium iodate
potassium bromate
H₂O₂

Reducing agents:
Hydrogen Sulphide
Fe²⁺
SO₂

[nid404]

Give
examples
of Oxidising agent and Reducing Agnet

Test for Oxidising agent

potassium dichromate is an oxidisng agent
Carbon, Carbon monoxide r reducing agents

but there r so many more depending on different redox reactions

testing....as in color change with change in oxidation state???
if so then ive ans it before.....u need to know manganate to manganese salt(reduction, color change from purple to colorless) and iodide to iodine(oxidation, colorless to brown)

[emi]

the thing is that if u see that markscheme and match it with the Question paper if doesnt match at all .. in Question paper the first Questions talk about liquid fuels obtained from petroleum while in the mark scheme it says 1) different boiling points ??

part b) says magnesium carbonate reactions with HCL to form a salt name that salt  
the markscheme says Volume decreases for forward reaction.


what i mean is that its not related at all  

[Kim]

test for oxidising agents
potassium iodide changes from colourless to yellow brown when added to a oxidising agent

test for reducing agent
add potassium dichromate colour colour changes from orange to green
add potassium manganate colour changes from purple to colourless

[nid404]

the thing is that if u see that markscheme and match it with the Question paper if doesnt match at all .. in Question paper the first Questions talk about liquid fuels obtained from petroleum while in the mark scheme it says 1) different boiling points ??

part b) says magnesium carbonate reactions with HCL to form a salt name that salt  
the markscheme says Volume decreases for forward reaction.


what i mean is that its not related at all  

i  think ur looking at 2 diff papers cuz it's perfectly matching for me.

[nid404]

ill put the question paper up for u emi