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Hey guys :smile:

There are so many damn formulas for the complex ions ! :/

please don't tell me I need to remember all these ? :frown:

For example hydrated Copper(II)chloride can be reacted with 4 moles of NH3
or 3 moles of 1,2-diaminoethane,
or 1 mole of ethanediaminetetraacetate
and so on...

to form all sorts of funky stuff ! ... its all just too much to remember ! :frown:

I'm referring to the george facer book :smile: I know it can be unnecessary, but I just want to make sure !
Reply 601
does anyone know what the max temperature for the reaction of benzene to form nitrobenzene is in markshemes ? i say 60 degrees is the temp is should be done at and it has to be above 55 but below 65 is that fine ?

different books say differnt things :redface:
thank you :smile:
Original post by jojo1995
does anyone know what the max temperature for the reaction of benzene to form nitrobenzene is in markshemes ? i say 60 degrees is the temp is should be done at and it has to be above 55 but below 65 is that fine ?

different books say differnt things :redface:
thank you :smile:


60 should be fine in the exam :smile:
hey guys, I just wanted to ask if anyone has this document that has all the chemical tests compiled together? I used to have it but I can't find it anymore, if anyone has it, can you please share a link?

(this is kindof a paper 6 request, but this is the only -active- thread i found)

thanks!
Reply 604
Original post by posthumus
60 should be fine in the exam :smile:


Thanks a lot :biggrin:
Do we need to know all the specific reactions of copper (I) and copper (II)???
There's too much to remember and it's all abstract and hard to learn.
Original post by lordmackery
Do we need to know all the specific reactions of copper (I) and copper (II)???
There's too much to remember and it's all abstract and hard to learn.


Original post by posthumus
Hey guys :smile:

There are so many damn formulas for the complex ions ! :/

please don't tell me I need to remember all these ? :frown:

For example hydrated Copper(II)chloride can be reacted with 4 moles of NH3
or 3 moles of 1,2-diaminoethane,
or 1 mole of ethanediaminetetraacetate
and so on...

to form all sorts of funky stuff ! ... its all just too much to remember ! :frown:

I'm referring to the george facer book :smile: I know it can be unnecessary, but I just want to make sure !


This.

I had the same question :tongue: Someone help us !!!! :smile:
Reply 607
Original post by posthumus
This.

I had the same question :tongue: Someone help us !!!! :smile:


You Defo need to know ammonia. We have learnt different ones such as EDTA, at my school and my teacher says we do need to know them ... I think they are more likely to be on mc though :smile:
This is going to sound like such a stupid question but it's something that I always mess up on in exam questions. :colondollar:

For redox, when working out the mole ratios do you just do the ionic equation or the whole compound? I've learnt the manganate one but I don't understand why it's the way it is. Why do you put MnO4- in it? Why not KMnO4? You only put the ion (Mn2+) for the product so why can't you put Mn5+ + 3e -> Mn2+ ??

Thank you. :colondollar:
Original post by jojo1995
You Defo need to know ammonia. We have learnt different ones such as EDTA, at my school and my teacher says we do need to know them ... I think they are more likely to be on mc though :smile:


Thanks !

Okay well I guess its not too much :smile: Just copper & chromium reactions to remember ? :smile: But I don't need to know the full name of EDTA or the structure of it right ? :colondollar:
Original post by LeaX
This is going to sound like such a stupid question but it's something that I always mess up on in exam questions. :colondollar:

For redox, when working out the mole ratios do you just do the ionic equation or the whole compound? I've learnt the manganate one but I don't understand why it's the way it is. Why do you put MnO4- in it? Why not KMnO4? You only put the ion (Mn2+) for the product so why can't you put Mn5+ + 3e -> Mn2+ ??

Thank you. :colondollar:


That's actually a good question :tongue: Usually the MnO4- is together as one ionic group - but I mean they usually want you to figure out that manganate is in the +5 oxidation state... you would only work that out if you had oxygen? (because that is what has oxidised the manganate ions in a way to make them in the +5 state, I think :smile: )

But in all honesty, I'm not sure why exactly :smile:
Reply 611
Original post by posthumus
Thanks !

Okay well I guess its not too much :smile: Just copper & chromium reactions to remember ? :smile: But I don't need to know the full name of EDTA or the structure of it right ? :colondollar:


Don't we need to know zinc as well? Fe also ? Who saîd we only need to know cr and cu? I thought we needed to know most if the top row if transition metals - fe mn cu cr zn and I cantvremember the others off head :tongue:
No you don't need to know the structure or real name of EDTA - just that it's charge is 4- and it has the ability to for 6 ligandish bonds
Original post by jojo1995
Don't we need to know zinc as well? Fe also ? Who saîd we only need to know cr and cu? I thought we needed to know most if the top row if transition metals - fe mn cu cr zn and I cantvremember the others off head :tongue:
No you don't need to know the structure or real name of EDTA - just that it's charge is 4- and it has the ability to for 6 ligandish bonds


Ah cr*p, your right :frown:

Okay that's a relief... and also some cations can have a certain number of ligands due to sizes of the atoms :smile: we don't need to remember how many ligands a cation can have? :redface:
Original post by LeaX
This is going to sound like such a stupid question but it's something that I always mess up on in exam questions. :colondollar:

For redox, when working out the mole ratios do you just do the ionic equation or the whole compound? I've learnt the manganate one but I don't understand why it's the way it is. Why do you put MnO4- in it? Why not KMnO4? You only put the ion (Mn2+) for the product so why can't you put Mn5+ + 3e -> Mn2+ ??

Thank you. :colondollar:


It's alot easier to see charges, because your given it, as an ionic equation!

I'm sure you know what I meant by ionic equations!

It's easier to see the charge on the atoms and hence allows you to see which got oxidised and reduced, more easily. :yy:
Original post by posthumus
Ah cr*p, your right :frown:

Okay that's a relief... and also some cations can have a certain number of ligands due to sizes of the atoms :smile: we don't need to remember how many ligands a cation can have? :redface:



Original post by James A
It's alot easier to see charges, because your given it, as an ionic equation!

I'm sure you know what I meant by ionic equations!

It's easier to see the charge on the atoms and hence allows you to see which got oxidised and reduced, more easily. :yy:


Thank you both. :smile:
Reply 615
Original post by posthumus
Ah cr*p, your right :frown:

Okay that's a relief... and also some cations can have a certain number of ligands due to sizes of the atoms :smile: we don't need to remember how many ligands a cation can have? :redface:




I think we do :redface: I keep breaking you bad news today :frown:

For eg cu+ forms cucl2
Whilst cu2+ forms cucl4

The reactions are in the blue edexcel book so I think you gosta know them.

Most of the transition metals fo compumounds w/ 6 h2os

Maximum nh3 is usually 4 so [cu(nh3)4(h20)2]

You don't have to include the h20 here if you don't want to :smile: fml I need to revise this stuff :redface:
Original post by jojo1995


I think we do :redface: I keep breaking you bad news today :frown:

For eg cu+ forms cucl2
Whilst cu2+ forms cucl4

The reactions are in the blue edexcel book so I think you gosta know them.

Most of the transition metals fo compumounds w/ 6 h2os

Maximum nh3 is usually 4 so [cu(nh3)4(h20)2]

You don't have to include the h20 here if you don't want to :smile: fml I need to revise this stuff :redface:


Aaaah damn :frown: More stuff to memorise !!

I guess I'll save memorizing for near exam time... I'm just going to try and make sure I understand every fundamental concept in all Chemistry units :smile:

Thanks for your help once again ! :biggrin:
Can somebody answer my question about copper please??
And do we need to know how to calculate Kstab? It's not in my textbook but it's in my revision guide?? Very confused.
Original post by lordmackery
And do we need to know how to calculate Kstab? It's not in my textbook but it's in my revision guide?? Very confused.


jojo1995 responded to your copper question (as well as my question) and yes you do have to remember all those reactions unfortunately. This unit has less new organic to remember - but there's a lot of redox/ complex reactions to remember also :tongue:

Erm I'm not too sure about that Kstab... but its only a very short part of the george facer book :smile: there's nothing really to remember Ka (from unit 4)... it's the same thing pretty much.

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