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3
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1answer
26 views

The walls of a plastic vial with Mercury inside are darkening. What is causing this?

I have a sample of Mercury in a plastic vial, The vial is a BD Vacutainer (genuine), made of polyethylene terephthalate. It is used for blood samples, and the one I used was new. When the vial was ...
3
votes
1answer
32 views

What is an effective fabric-friendly solvent for aluminium chlorohydrate?

I have recently found out that the white/yellowish "sweat" stains one occasionally finds on t-shirts might be aluminium chlorohydrate polymers. While talk about aluminium and antiperspirants is all ...
0
votes
2answers
50 views

How are electrons in conjugated molecules excited? [duplicate]

I have recently started reading about colour in organic molecules and come across conjugation of pi bonds. My question is pretty short... In transition metal ions I understand colour is caused by ...
2
votes
1answer
48 views

Why is $\ce Co(SCN)_4$ blue?

Why is $\ce Co(SCN)_4$ blue? I simply can't predict the colors of such inorganic salts. I have learnt that $\ce {Co^{2+}}$ salts are pink in color. Also, if the ligand is a strong field ligand ...
0
votes
1answer
60 views

Does Nitrogen dioxide change colour if we put it in a constant temperature of e.g. 100 kelvin?

The changing of the colour of $\ce{NO2}$ is because of a change in temperature, resp. heating and cooling?
1
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1answer
77 views
2
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3answers
472 views

what is the origin of the colour of azo dyes?

what is the origin of the colour of azo-dyes? Is it the same reason as to why transition metal complexes have colour?
1
vote
3answers
111 views

How do i find out which species is colourless? [closed]

Among the following $$\ce{TiF6^{2-},\ CoF6^{3-},\ NiCl4^{2-},\ CuCl2}$$ how do i find the species which i colorless If possible please provide the concept used to deduce the result it will be very ...
1
vote
2answers
111 views

Why does ZnO turn yellow when it is hot?

Why does ZnO's color become yellow when it is hot? I have read that it is because of physical properties, but I need a more elaborate explanation.
4
votes
1answer
192 views

Can I synthesize iron acetate like this?

The oxidation state of the iron doesn't matter too much; I am just trying to make an attractive red-brown ink. Here are some instructions I prescribed to a friend. Here's an approximately decent ...
1
vote
0answers
75 views

What reaction took place?

Okay, so I was fiddling about in the chemistry lab, and I added: Sodium Nitroprusside (soln) $\small\ce{ Na_2[Fe(CN)_5NO] }$ with Potassium Ferrocyanide (soln) $\small\ce{ K_4[Fe(CN)_6] }$. ...
3
votes
3answers
120 views

Can you colour a flame, and what would the effects be?

I read this question : Flame temperature for cooking food and was thinking, could companies colour there flames so that products would heat quicker? how would they do this, also could you use this to ...
1
vote
2answers
127 views

Egg-Detection in Pastries: An Analysis in Heat-Alterated Molecule Identification

I would like to know if anybody here knows of a method to detect the presence of ovalbumin--or any unique, egg-related molecule, in a baked good. Here I am anticipating that the "unique egg-related ...
1
vote
1answer
110 views

How Does The Mordant, Ferric Acetate, Interact With Tannins When Ebonizing Wood?

Ferric Acetate (II) and (III) are "mordants," which intensify wood staining in direct proportion to the tannin concentration in the wood. Some wood stainers add tea to increase the tannin content and ...
6
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2answers
4k views

Why do transition elements make colored compounds?

Why do transition metals element make colored compound both in solid form and in solution? Is it related with their electrons or something else?
4
votes
1answer
82 views

Is it possible to calculate chromacity coordinates using absorbance values?

I have absorbance values for blood plasma. Absorbance was measured in range of 380 – 600 nm every 5 nm ending up with absorbance values for 45 wave lengths. I was browsing through literature, and I ...
3
votes
1answer
88 views

What causes Copper Rose?

We made a solution of Tetrakis Copper(I) hexafluorophosphate and the usual color is yellowish. As it oxidizes to Cu(II), it should turn blue. However, our current mixture has an off color that is ...
12
votes
2answers
4k views

Why are some salt solutions coloured?

I notice that salt solutions of $\ce{NaCl}$ and $\ce{KCl}$ are colourless while those of $\ce{CuSO4}$ and $\ce{FeSO4}$ are coloured. I got as far as figuring that it has to do with the transition ...
5
votes
2answers
193 views

What chemical compounds were used in CRT phosphors?

In the old days computer monitors and televisions were built from cathode ray tubes (CRTs) where the image was generated by an electron beam hitting phosphors which emitted light approximating the ...
3
votes
1answer
77 views

Question about fire and colors

Most solids objects turn black after they are burnt. But some turn white. Why is that ?
14
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3answers
889 views

How may copper acetate ligands be manipulated to change colors?

I have a solution of copper acetate and I would like to play around with the ligands to get different colors. Background: The copper acetate was made through mixing vinegar (5% acetic acid), NaCl, ...
9
votes
2answers
671 views

Color of chromate and permanganate

I've heard quite a few times that the chromate and permanganate have a $d^3s$ configuration. Also, their colors arise due to a rapid switching of electrons between the oxygen and metal atoms. I don't ...