Questions tagged [color]

Questions where color (wavelengths associated with the visible region of the electromagnetic spectrum of about 400-800nm), or a color change is discussed.

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1answer
120 views

Analysis of cations using sodium thiosulphate

A question in an exam was as follows:[1] How many of the following salts are first soluble in $\ce{Na2S2O3}$ solution, followed by the formation of a white precipitate and finally the precipitate ...
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38 views

What characterises the smell of alkane hydrocarbons?

I have heard that aromatic hydrocarbons smell fruity and like petrol. However, I understand that there is a class of hydrocarbons called alkane, as for example propane or butane. I wondered if I might ...
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Is it necessary that all transition metal complexes with unpaired electrons will show color?

For example consider the complex ion $\ce{[Mn(CN)_6]^{3-}}$ , it is octahedral so its d orbitals will split like $\ce{t_{2g}^4e_g^0}$. I understand the basics of how complex compounds show color (that ...
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1answer
63 views

Why did ammonium chloride fumes turned pink in this synthesis?

I was watching the synthesis of tetrasulfur tetranitride performed by Tom on his Youtube channel, Explosion & fire. He followed the basic route: adding ammonia gas to sulfur chlorides ($\ce{SCl2}$ ...
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1answer
33 views

Actual color of colloids [closed]

I have read that the color of colloid depends upon the wavelength of light scattered by the dispersed phase and also in the sense in which the receiver receives the light. If all of this depends on ...
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1answer
71 views

Why aren't solid pure transition metals colourful?

I understand that the compounds of transition metal are colourful because of the appropriate energy gap between different d orbitals. But why aren't they also colourful in their solid pure state? For ...
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2answers
109 views

Controlled burn with colored flames (Gender Reveal) [closed]

Is there a single solvent that can dissolve chemicals/elements that when burned, will produce the color of its respective chemical/element? If so, what chemical/element can be dissolved in this ...
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2answers
206 views

The color of the most sulfides of p- and d-block elements

My teacher said that many of the sulfides of d-block and p-block are black. Why?
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1answer
75 views

What is the main contributor of the color of honey? [closed]

I was told that the color of honey contains so much chemistry and that was interesting to me and after doing a couple of research I found that the color of honey depends on the presence of plant ...
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4answers
157 views

Chemical elements or compounds with yellowish white color [closed]

Are there chemical elements or compounds that have a yellowish white (cream) color in their natural state?
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1answer
82 views

Colour due to transmission and reflection

It makes sense to me that when looking through a sample (observer | sample | light), it should appear as the opposite of the light absorbed, but it does not make sense to me to expect the same when ...
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1answer
44 views

Which is a dye: Ferric Acetate or Ferrous Acetate?

I’ve been trying to make Iron Acetate to dye leather and I cannot, for the life of me, figure this out experimentally. I’ve been allowing steel wool to react with pure white vinegar in a sealed glass ...
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0answers
46 views

Why are sulphide salts of p and d block coloured?

I have studied that sulphide salts of s block are colourless while p and d block salts are coloured. But colour intensity of a salt is directly proportional to polarisation in salt. And s block ...
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2answers
41 views

Water color additive that will maintain color when water is a thin film

I'm producing thin sheets of liquid (50 to 100 microns) from a nozzle and trying to photograph them. I think it would help if I could color the water. However, typically as water becomes more of a ...
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2answers
70 views

Titrating iodine starch solution with sodium thiosulphate - Colour change

I investigated two mixtures with different solvents, one with water and one with n-heptane. Both contained iodine $\ce{I2}$ as a solute. To both solutions I added a bit of starch. As I remember this ...
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0answers
32 views

Measuring ions through color change during electrolysis

I have very little experience in chemistry, you might consider me a physicist, and I am mostly not even sure where to find the information I need. I will start off by describing my problem, I have a ...
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0answers
74 views

Why are polynuclear carbonyl complexes coloured?

We know that polynuclear carbonyls are colored and their intensity increases with increase in metal ions. But why does the color arise? I am aware that this is due to some transition between ...
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0answers
44 views

Why are Buckminsterfullerene (C60) solutions pink/purple?

A solution of Buckminsterfullerene $\ce{(C60)}$ is shown below: According to the April 8th Wikipedia page on Buckminsterfullerene $\ce{(C60)}$: Solutions of pure C60 have a deep purple color which ...
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1answer
37 views

Can a spectrometer be used to figure out spice ratios in a sauce?

There is a really good sauce that a local restaurant makes. I have had trouble recreating it, but have gotten somewhat close. I had the following idea: I could take an "image" of the sauce's color ...
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40 views

Effect of optical isomerism on colour of transition metal complexes

I know that different stereoisomers of a given transition metal complex (cis- and trans- forms) have different colours. But do different optical isomers (non-superimposable mirror images) have ...
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0answers
41 views

Blue bottle experiment turning yellow after being left alone

I conducted the blue bottle experiment, mixing glucose, sodium hydroxide and methylene blue and shaking to produce a blue colour, which turns colourless after a while due to the reduction of methylene ...
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2answers
339 views

Is there a way to create natural Red food coloring from Turmeric in the house kitchen?

As a non chemist I have read in the Wikipedia article Curcumin that: Curcumin becomes bright red when it interacts electrostatically with phospholipid film. This text appeared without source ...
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0answers
52 views

Looking for color changing reaction to track snow layer depth

I'm trying to find a chemical to mark the position of a snow layer with for detection in future seasons. The substance has to be: 1. Colorless 2. Not water soluble/solid 3. Stable for multiple years ...
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1answer
58 views

Some substances appear white when crushed while others do not. Why?

Calcite crystals are semi-transparent but turn white when crushed. I used to think that it has something to do with the scattering of all wavelengths of light from small particles. But that cannot be ...
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0answers
104 views

Colour of VO3^-?

To aquire the yellow colour of vanadium ion, it must be present in a 5+ oxdiation state. This can be acheived (according to my textbook) by adding dilute sulfuric acid to $\ce{NH4VO3}$, then followed ...
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1answer
156 views

Why is chromate coloured but tungstate colourless?

I have to try and work this out using the tetrahedral molecular orbital diagram for $\ce{[WO4]^2-}$ but I am confused as both are $\mathrm d^0$ right?
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2answers
486 views

Predicting colors of aqueous solutions

While going through my AP chem prep book again, I came across questions asking about the color of certain aqueous solutions. For example: Which of the following substances will produce a colorless ...
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1answer
95 views

Why does the colour of the same compound (e.g. magnesium nitride) differ?

When I am searching the colour of $\ce{Mg3N2}$ I came across photos showing different colours: greenish-yellow on Wikimedia, and some other just yellow on some Google Images results. I am eager to ...
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1answer
30 views

Predicting color of a TMB derivative affected by peroxidase

The ELISA test on HIV works by verifying the presence of peroxidase within samples. The verification process is done through the enzymatic reaction that said peroxidase has on TMB (3,3',5,5'-...
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0answers
67 views

What is the right color of calcium copper titanate?

I'm browsing Alibaba for calcium copper titanium oxide $\ce{CaCu3Ti4O12}$ (CCTO) and I find it variety of colors: pure brown, pale brown, reddish brown or grayish dark brown. Wikipedia does not tell ...
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4answers
3k views

Explanation for why nickel turns green in hydrochloric acid

My daughter has a chemistry test that I am helping her prepare for. One question is Nickel sulfate, $\ce{NiSO4(aq)}$ is a green solution. Nickel chloride, $\ce{NiCl2(aq)},$ is a yellow solution. If ...
2
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1answer
73 views

Why does the displacement reaction of zinc in copper(II) sulfate solution result in dark metallic copper?

It is commonly known that when zinc metal is placed in a solution of copper(II) sulfate, a displacement reaction occurs, and elemental copper is deposited onto the decomposing zinc metal. A practical ...
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21 views

What solvents can solve aromatic urethane resins?

Do you have any information about chemical resistance of hexa-functional aromatic urethane acrylate? I want to know what solvents can solve aromatic urethane resins.
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38 views

Mixing ink with alcohol, MEG and water

First of all, I'm not a chemist and my knowledge in chemistry is not that extensive. However, I would like ask the following question: are there any chemical reasons that would explain that mixing a ...
2
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1answer
112 views

What gives rise to the color of sapphires?

Here is what I know: Sapphires are composed primarily of $\ce{Al2O3}$ (in pure form colorless) as well as Fe and Ti (trace impurities responsible for the color). I know that the proportion and ...
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1answer
91 views

Does a complex that has no overall charge still have color?

The iron complex $\ce{[Fe(H2O)6]^2+}$ is colored but I'm wondering, if a pair of chloride ion is inserted on its secondary valency to form [FeCl2(H2O)6], does the complex loose its color or not?
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52 views

Does something like a fluorescent foil or a fluorescent film exist?

During my experiments I want the emitted laser beams to come back with a different wavelength than the original wavelength using a fluorescent foil or fluorescent film. The laser I'm currently using ...
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0answers
43 views

Comparing the emission spectrum of ethanol and mixture of alcohols

Sorry if this question has a simple answer, but I've been unable to find it elsewhere. Using a diffraction grating, burning ethanol (99.9%) will produce a rainbow of colours. However, when burning ...
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0answers
1k views

Mechanism of DPD (N,N-diethyl-p-phenylenediamine) reaction with free chlorine

NOTE: As I've been finding new informations about the question, I've been editing the question to keep it up to date. If some comment doesn't make sense just check the Edit History. DPD (N,N-diethyl-...
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0answers
28 views

Two common fluids that don't mix inside a labyrinth [closed]

I'm not sure in which SE site put this question. Imagine a typical child toy, where a bunch of spheres move by gravity through a labyrinth. Now imagine a sealed small labyrinth with two fluids. I'd ...
2
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1answer
85 views

What easily available chemicals do I use to turn oak light grey?

I have 10 square meters of dry and freshly sanded oak that I would like to artificially age/weather to the colour of the above photo. Once treated the oak is to be used for a bedroom interior. I was ...
3
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1answer
227 views

Why are most glow-in-the-dark things green?

I've noticed that many glow-in-the-dark objects you can purchase in the store are green. Occasionally I would come across something that was orange or blue, but mostly it seems that green is the ...
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0answers
53 views

Why does my rainwater turn yellow if I increase the pH to 7?

My rainwater is colourless when collected, but if I add a small amount of sodium hydroxide to increase the pH to about 7, after a few days it goes yellow. The colour change happens more quickly if I ...
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1answer
58 views

Why is the reason for color different in these two cases? [closed]

I have read in a book (NCERT India) about flame color for salts of alkali metal and color of transition metal complexes. In the first case, it says that during excitation of electrons to higher ...
13
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1answer
1k views

What exact color does ozone gas have?

This answer to a now closed question says that ozone gas has a "slight blue" color. But there are lots of blue colors: sky blue, ultramarine, phthalo blue, many others — what is closer to the color of ...
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1answer
2k views

How to determine the greatest d orbital splitting?

This question comes specifically from an IB Chemistry HL Paper 1 in May 2018 TZ1, namely question 8. Which complex has the greatest d orbital splitting? It gives 4 Complexes $\ce{[Fe(H_2O)_6]^{2+}}$,...
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0answers
41 views

Reduction of triphenylmethane dyes in ink

Right now I'm trying to explain why the ink from an ink pen turns colourless in water. I know that the pH is responsible as it breaks apart the conjugated system of double bonds. I'm just not sure on ...
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1answer
1k views

Potassium Manganate and Acidified Potassium Dichromate colour changes [closed]

I would be obliged if somebody could explain the colour changes for the reduction of potassium manganate and acidified potassium dichromate. I understand that for potassium manganate, it is being ...
0
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1answer
1k views

Why does the colour of gold sol change with particle size? [duplicate]

Regarding the colour of gold sol, my book says Finest gold sol is red in colour; as the size of particles increases, it appears purple, then blue and finally golden. This is the image I found on ...
5
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1answer
724 views

Colour of colloids

Why colours of colloidal solutions are different when viewed along different directions? For example Milk appears blue when viewed by reflected light and red when viewed by transmitted light Is it ...

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