Determine Color of Solutions: Co(NO3)2, KMnO4, Na2Cr2O7, ZnCl2

[Asian Girl]

How do we determine color of solution? For example: Which compound forms a colorless solution when dissolved in H2O? a. Co(NO3)2 b. KMnO4 c. Na2Cr2O7 d. ZnCl2

Thanks.

 

[C3H5N3O9]

The answer would be d.

You just have to memorize basic compound colors.

 

[Asian Girl]

The answer would be d.

You just have to memorize basic compound colors.

Would you give me the list of basic compound colors please?

 

[C3H5N3O9]

I apologize, but I don't have a list. Although when zinc is in the compound, it is often colorless.

Try searching the compounds on google. Wikipedia would also provide information and pictures of the compounds.

 

[mgb_phys]

There is a partial list here http://en.wikipedia.org/wiki/Colors_of_chemicals
Remember that the colour also depends on the oxidations state
so Cu+ (eg Copper Oxide) is black, Cu++ (eg copper sulphate) is blue and Cu+++ (eg copper chloride) is green.

 

[Hurkyl]

Surely this information is in your textbook, or your course notes...

 

[Asian Girl]

I don't remember i saw list of colors in my textbook but I did in lab once with cooper which was blue. That's all.
Thanks for the website. It helps.

 

[Asian Girl]

Another question

I have 2 questions about diagrams but I don't know how to copy it in here. Would someone show me how to do it?

 

[C3H5N3O9]

Take a picture and upload it, or use a scanner if you have one.

 

[Asian Girl]

I copied but I could not paste in here.

 

[Redbelly98]

I have 2 questions about diagrams but I don't know how to copy it in here. Would someone show me how to do it?

When you're composing a message in here, click the "Go advanced" button below the message. In the new message window that comes up, click the paperclip icon (next to smiley face), and take it from there.

 

[GCT]

If this question pertains to inorganic chemistry in college you may need to utilize the Tanabe-Sugano diagrams otherwise utilize the crystal field theory with the water molecule as ligands - if this question is for general chemistry the ligand arrangement is probably going to be hexagonal and then you need to figure out the field type. Asiangirl you're just going to need to reveal to us a bit more about the assignment and what class this is for. Inorganic chemistry is not the same course as general chemistry in college.

 

[Asian Girl]

If this question pertains to inorganic chemistry in college you may need to utilize the Tanabe-Sugano diagrams otherwise utilize the crystal field theory with the water molecule as ligands - if this question is for general chemistry the ligand arrangement is probably going to be hexagonal and then you need to figure out the field type. Asiangirl you're just going to need to reveal to us a bit more about the assignment and what class this is for. Inorganic chemistry is not the same course as general chemistry in college.

General Chemistry I in college

 

[GCT]

Then my guess is that he's testing you on common knowledge - there should be a section in your textbook devoted to hexagonal ligand arrangements with water for crystal field theory -the answer should be located there simply browse through and find it. There are systematic ways to find the color using this theory - has your professor mentioned it?

 

[MichaelXY]

I think ligands and crystal field theory are more of a Chem II subject. I say this because that topic is near the end of my chem book (Brown Lemay et.al) and our book is a 2 semester book, so I assume Chem II. I am just now completing chem I, and we never covered Ligands and Xtal theory.

 

[Asian Girl]

It may be Gen Chem II because I am practicing ACS old exam. Those tests may have all Chem I and II, that why some questions they did not bring any bell at all.

Thanks guys.