CHEM AND BIO HELP AND TIPS HERE

[NidZ- Hero]

can any 1 exactli show hw u do we this question

Draw a diagram to show the arrangement of the valency electrons in one molecule
of the covalent compound hydrogen sulphide.
Use o to represent an electron from a sulphur atom.
Use x to represent an electron from a hydrogen atom
 

[Baladya]

This is a probably a really dumb doubt but I'd appreciate if someone could please kindly answer it.

I'd just like to know in an electrochemical cell, when the more reactive metal loses the electrons and becomes a positive ion, I just wonder why here it becomes the negative cathode.  And the less reactive metal gains the electrons becomes the positive anode?

I think this has to do with electricity: From negative to postitive....
not sure tho

[Vin]

This is a probably a really dumb doubt but I'd appreciate if someone could please kindly answer it.

I'd just like to know in an electrochemical cell, when the more reactive metal loses the electrons and becomes a positive ion, I just wonder why here it becomes the negative cathode.  And the less reactive metal gains the electrons becomes the positive anode?

Well, as the more reactive metal gives e-, it is a source of -ve charge hence it is called the negative pole.. You see it isn't really the "cathode", its just

the -ve terminal of the battery.. same goes for the +ve terminal and not "anode".

The diag. unnecessary I guess...

[Ivo]

Well, as the more reactive metal gives e-, it is a source of -ve charge hence it is called the negative pole.. You see it isn't really the "cathode", its just

the -ve terminal of the battery.. same goes for the +ve terminal and not "anode".

The diag. unnecessary I guess...

Nah, good diagram and explanation!  Thanks!!!   Just another thing, so electrons flow from the negative pole to the positive pole through the external circuit in wires, whereas ions move through the electrolyte?

[Vin]

thx vin so anything above mg doesnt react wiz double bonds like alkenes but can u explain reason for that plz and for other question i meant q 5 c iii nov 07 just one more last thing can anyone upload a guide for finding limiting reagent from equation

I am really sorry, I don't really know the 'accurate' info. about it, also I don't think we have to know about it. So if a question like this turns up, stick to the other options like carbonates, oxides etc.

Ah, yes a strong base can effectively displace the weak salt. Simpler eg. 2NaOH  +  CuSO4 ---> Na2SO4  +  Cu(OH)2
My apologies again 7ooD  I don;t have any guide based on limiting reagent
Also google "how to find limiting reagent", you'll get many links..

[Baladya]

Nah, good diagram and explanation!  Thanks!!!   Just another thing, so electrons flow from the negative pole to the positive pole through the external circuit in wires, whereas ions move through the electrolyte?

yes

[Vin]

can any 1 exactli show hw u do we this question

Draw a diagram to show the arrangement of the valency electrons in one molecule
of the covalent compound hydrogen sulphide.
Use o to represent an electron from a sulphur atom.
Use x to represent an electron from a hydrogen atom
 

Hydrogen Sulfide = H₂S

H - 1
S - 2, 8, 6

would be something like..

                     oo
                o           o
            H        S           H
                x            x
                      oo

[$H00t!N& $t@r]

can some1 pls explain why theres no reaction when potassium hydroxide decomposes

[Vin]

thx vin so anything above mg doesnt react wiz double bonds like alkenes but can u explain reason for that plz and for other question i meant q 5 c iii nov 07 just one more last thing can anyone upload a guide for finding limiting reagent from equation

Have a look at this!

http://wiki.answers.com/Q/How_do_you_solve_limiting_reagent_problems

^^ a lot but read the starting part..

[CatAly$t]

somebody pls explain to me this...

[Vin]

can some1 pls explain why theres no reaction when potassium hydroxide decomposes

Sodium carbonate and Potassium carbonate, even when heated to a high temperature, do not decompose.

Sulphites of sodium and potassium do not decompose when heated.

Lowest oxides of metals (K2O, MgO, Al2O3) do not decompose when heated:: Exceptions Mercury and silver oxides decompose when heated, ZnO- yellow when hot, white when cool.

Don't ask why because they are not supposed to decompose WHEN HEATED..

[$H00t!N& $t@r]

no problem..
anyways

the vol. of phosphate soln used in cm3 is half the height of the ppt in mm
also at 8cm3 all the soln is used up. tht is because adding more does not increase the height of the ppt meaning there was no further reaction on adding more.
also the formula is T3(PO4)2-----because

u take it as 12cm3 of T nitrate react with 8cm3 of sodium phosphate (thts wen all the reactants r used up)
so.....12:8...simplify it
12:8
6:4
3:2
and therefore u get T3(PO4)2

this answers ur question catalyst

[$H00t!N& $t@r]

Sodium carbonate and Potassium carbonate, even when heated to a high temperature, do not decompose.

Sulphites of sodium and potassium do not decompose when heated.

Lowest oxides of metals (K2O, MgO, Al2O3) do not decompose when heated:: Exceptions Mercury and silver oxides decompose when heated, ZnO- yellow when hot, white when cool.

Don't ask why because they are not supposed to decompose WHEN HEATED..

k Thanks ill try to keep this in mind

[Vin]

k Thanks ill try to keep this in mind

There are more I guess.. I can't recollect them. Unfortunately nothing in the book

[rhea]

There are more I guess.. I can't recollect them. Unfortunately nothing in the book

what about nitrite?

nd sulphite and carbntes of ONLY NA and K do not decompose?