[lwl]

I am sorry that I have to ask questions again. I am revising my chemistry examinations and the colour of the compounds make me confused. Do you have any suggestions to me that can make me easier to remember the colour changes?

In fact I am a student from Macao . In my chemistry lessons, we just seldom carry out the experiments and so I cannot remember the colour changes through experiments.

Moreover, except the colour changes, are there any extra and important things that I need to be careful for?

A little help would be appreciated. Thanks.

[Arkcon]

Try to study example problems that you've been assigned, and if you can't solve them, post the problem, and your attempt, and we'll see where we can help. 

If you've been assigned to memorize compound, or gas colors, then do so.  There's no way for us to give you hints on that sort of thing.

Try some of the other problems you've seen posted by others on this forum, can you solve those, or can you understand the help we've given people?

[lwl]

Okay. I will try to see the problems that posted by others. If I have other problems, i will post it here. Thanks.

[Astrokel]

What colour changes are your experiments about?

[lwl]

In fact it is a question like this.
These exercises is about metal and reactivity series.
She ask us to give ionic equations for those that occur and describe what you expect to see.

One of the questions is the reaction about iron filings and copper(ii) sulphate solution.
I know how to write the ionic equations.
And I said that the colour would change from blue to green.
Am I wrong? Or should I mention the other observance rather than colour changes?
Since I think that CuSo4 is blue is colour and FeSo4 is green in colour.
Or should I said that there is a layer of reddish brown copper on the surface of the solution?
I said that it is hard to remember the colour changes is because I forgot the colour of FeSO4. Moreover, the colour of CuSO4 also made me confused. ( Sometimes it is white and sometimes it is blue...

Moreover, there is also one question. ( It is also write the ionic equations and observance.)
Lead powder and silver nitrate solution.
I also know how to write the equations.
However, I cannot think of the changes.

At last, there is a question. She ask us to think out what these metals ( X,Y,Z ) are.
First there are three solutions. ( XCl2, YSO4, ZSO4 )
When Y or Z is put in XCl2  no visible changes.
When X is put in YSO4 pink deposit on X
When Z is put in YSO4 pink precipitate
When  X is put in ZSO4 black precipitate
When Y is put in ZSO4 no visible change.

From the information above, I can only know that X>Z>Y ( I mean reactivity. ) And I cannot guess these three metals. I don't understand that pink precipitate. ( I haven't studied one precipitate that is pink.) So I feel confused.
 
I am sorry that I have asked so many questions. But this makes me confused. A little help would be appreciated.

At last, I would like to ask, if the question ask us to observe what will happen, usually should I mention colour changes or other things? Thanks.

[Astrokel]

One of the questions is the reaction about iron filings and copper(ii) sulphate solution.
I know how to write the ionic equations.
And I said that the colour would change from blue to green.
Am I wrong? Or should I mention the other observance rather than colour changes?
Since I think that CuSo4 is blue is colour and FeSo4 is green in colour.
Or should I said that there is a layer of reddish brown copper on the surface of the solution?
I said that it is hard to remember the colour changes is because I forgot the colour of FeSO4. Moreover, the colour of CuSO4 also made me confused. ( Sometimes it is white and sometimes it is blue...

At last, I would like to ask, if the question ask us to observe what will happen, usually should I mention colour changes or other things? Thanks.

You are pretty right on the observation. Observations could be colour change, gas formed, precipitation, pH and many more. You are right that CuSO₄ is blue while FeSO₄ is greenish(or in fact blue-green) and also on the layer of reddish brown copper formed.

Most copper(II) compounds are blue in colour is because of Cu²⁺(aq) ion which is [Cu(H₂O)₆]²⁺. Once you heat off the water molecules, the copper(II) compound will be white in colour. For Fe²⁺(aq) solution it is blue-green while Fe³⁺(aq) is yellow solution. You notice SO₄^2-(aq) is colourless, so the end result of colour will be dependepnt upon the cation.

Moreover, there is also one question. ( It is also write the ionic equations and observance.)
Lead powder and silver nitrate solution.
I also know how to write the equations.
However, I cannot think of the changes.

Basically you have to know the colours of each metal(Ag & Pb) and compounds formed to state the observation. Try memorizing some and do more practices, it will come easy.

At last, there is a question. She ask us to think out what these metals ( X,Y,Z ) are.
First there are three solutions. ( XCl2, YSO4, ZSO4 )
When Y or Z is put in XCl2   no visible changes.
When X is put in YSO4  pink deposit on X
When Z is put in YSO4  pink precipitate
When  X is put in ZSO4  black precipitate
When Y is put in ZSO4  no visible change.

You are correct about the reactivity series. Good one. Give this question a few more attempts. The hint is that d-block metals and usually coloured. Try google or look into text.

[lwl]

I am sorry that I fail on the research.
I can just little information on it.
But I guess... The metal Y... is it copper?
X and Z... I still cannot find anything about them.

Moreover, can you give me some colours of the metals that is on the reactivity series?
Are all Group1 metals shiny white in colour?
How about Group2 metals and others?

[UG]

Yes, I am pretty certain Y is copper, and I think Z is iron and X is zinc (but I am not too sure about Zinc  ).

[Astrokel]

I'm thinking the pink ppt could be cobalt(II) sulphate. Anyone given any thoughts?

[lwl]

I have some thoughts on it, but I don't know whether I am right or not.

I have checked my book, it said that cobalt(ii) ion is pink in colour.
But... is it change to grey when it is in solid state? ( I am not sure about it )

If I am wrong...please tell me. A little help would be appreciated.