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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3
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1answer
91 views

Reaction between anilinium chloride with ferric chloride

I have a question about reaction between aniline and $\ce{FeCl3}$. I supposed that the following reaction proceeds with formation of brown precipitate: $$\ce{3C6H5NH2 + FeCl3 + 3H2O -> \underset{...
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4answers
227 views

When pigments absorb light only around a single particular wavelength, why aren't they still white?

I'm trying to understand how organic molecules get their colour. One major factor are conjugated double bonds which create delocalized pi-orbitals (e.g. https://en.wikipedia.org/wiki/...
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0answers
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Briggs-Rauscher reaction doesn't oscillate and turns blue with Vitamin C

I tried to recreate the Briggs-Rauscher reaction by using a solution of $\ce{H2O2}$, $\ce{KIO3}$, $\ce{H2SO4}$, $\ce{CH2(COOH)2}$, $\ce{MnSO4}$ and a soluble starch. I used this recipe. In container ...
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1answer
36 views

How can one change the color of Iron Oxide by changing the composition or hydration?

How does the color of rust change depending on its makeup and state, or more to the point, how would one put the rust into that state? For example, Wikipedia shows Iron(III) Oxide as being red in the ...
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0answers
53 views

What causes the amber/colourless/blue colours in the Briggs-Rauscher oscillating reaction?

I am using this commonly cited but simplified reaction mechanism of the Briggs-Rauscher reaction. Reaction 1 & 2 occur simultaneously. For reaction 1, when the iodide concentration is low, the ...
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0answers
26 views

The mechanism of discoloration due to changes in the state of CP

I don't know the mechanism of discoloration due to phase change. https://pubs.rsc.org/en/content/articlelanding/2019/cc/c9cc02172h In the above paper, Cu(I) in CP1 (Figure 1 a) has a tetrahedral ...
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33 views

Are there any pathways that can change a solution to all colors of the rainbow?

The challenge's like this. Suppose you have a beaker containing a liquid of transparent or any color. You add some drops of another liquid and the beaker turns into, say, red after some swishing. You ...
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1answer
80 views

How to predict colour of precipitate? [duplicate]

I am currently preparing for Junior science competitions and I am coming across many questions where colour of precipitate plays important role... Like When compound $\ce{Hg2(NO3)2}$ reacts with $\ce{...
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1answer
135 views

Cobalt glass colour of potassium as

Question: Cobalt glass colour of potassium as: A) Crimson red B) Lilac C) Apple green D) Brick red I thought option B as true because on flame test, potassium gives lilac colour. But the given ...
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1answer
333 views

What is the colour of cesium?

I am confused with the color of cesium. Some websites and books say that it is a silvery white metal, and some say it has a golden colour, and some say it has a silvery golden colour. Among these ...
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2answers
315 views

What is the chemical composition of Ferrous Ferrocyanide?

To this day, iron-cyanide complexes confuses me. So, I want to settle this once and for all. After scavenging the internet, I gathered the following result: $$ \ce{Ferr} \color{blue}{\ce{ous}}~\ce{...
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1answer
45 views

What replaced lead-based pigments? [closed]

In the 1960s and before, even black and white letters had some lead from the actual metallic letters used by typesetters—some rubbed off. Same thing with books printed before 1970 or so and libraries ...
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1answer
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Looking for gas or liquid for story research

I am working on a story for adaptation into animation. Main lead is a chemist in a traditional fantasy setting. The chemist uses her own compound to battle using fire or explosions. I love the ...
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1answer
84 views

Lithium Oxide Colour

According to Chemistry LibreText: Lithium is the lightest of all metals and is named from the Greek work for stone (lithos). It is the first member of the Alkali Metal family. It is less dense than ...
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1answer
139 views

Ferrous chloride solution coming out purple rather than green?

I've got some steel wool in hydrochloric acid to attempt to make ferrous chloride and the whole solution has turned purple. From everything I've seen it's supposed to be green. I have no idea what's ...
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1answer
99 views

Nomenclature of Colors of precipitates and solutions

I have just started learning salt analysis in inorganic chemistry. In it i came across the names of colors of various precipitates and solutions. Why do they have prefixes such as "scarlet" ...
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224 views

Comparing intensity of colour in coordination compounds

I had given an examination recently in which the question asked was: Write the decreasing order for the intensity of color in $\ce{[CoCl4]^{2-}}$, $\ce{[Co(CN)4]^2-}$, $\ce{[Co(H2O)6]^2+}$ What my ...
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1answer
159 views

Why do boron salts impart a characteristic green colour to the flame

In salts of boron it exists as a cation in the B(III) form. It is known to impart green colour in several of its salts like borates, boron triflourides, boric acid etc. If there are no electrons in ...
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36 views

How do I anodize bronze for thin film colors using electrolysis?

I am trying to change the color of the coins we have in Europe. I want to create patterns of certain colors. They are made from "nordic gold" (89% copper, 5% aluminum, 5% zinc, and 1% tin). ...
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0answers
53 views

What caused a colour change when I mixed two different dish soaps?

I recently purchased "organic" dish soap refill made from saponified coconut oil and potassium soap (full ingredient list). Instead of waiting for the old dish soap (Dawn) to be completely ...
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1answer
73 views

The color of resorcinol-formaldehyde resin

At school, I did an experiment of synthesizing resorcinol-formaldehyde resin. When I added $\ce{NaOH}$ and gave some heat, the color of resorcinol-formaldehyde resin inside the test tube became ...
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0answers
45 views

Is there a known value for the molar extinction (absorption) coefficient for amylose and amylopectin iodine complexes?

I am doing a colorimetry experiment with starch, and have a theoretical model based on Beer's law. To solve it, I need a known value for the molar extinction coefficients of amylose and amylopectin ...
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1answer
358 views

Flame Test of Alkali Metals and Alkaline Earth Metals

The flame test colors for alkali metal and alkaline earth metal salts are well known, but what about the metals themselves? Do they also give rise to the same colors (eg, brick red for Ca, pale green ...
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2answers
2k views

Why is bleaching with chlorine permanent but with sulphur dioxide temporary?

I was reading the properties of chlorine when I came across this statement: Chlorine is a powerful bleaching agent; bleaching action is due to oxidation. Chlorine bleaches vegetable or organic matter ...
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0answers
26 views

What color would be produced by the burning of the listed chemicals of the projectile weapon the carcass?

The carcass was a projectile weapon developed by the French in the second half of the 17th Century. It was "named carcass because the circles which pass from one ring, or plate, to the other, ...
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1answer
75 views

Why is my dried out copper sulphate green when wetted with water?

I dried out some blue copper sulphate in an oven to see if it would turn white which it did. I can't remember exactly but I left it overnight in the oven at around 50 C. It was white the following day....
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2answers
92 views

The colors that we see [closed]

I have a question. When I was studying Coordination Compounds, I came across this para: When a sample absorbs light, what we see is the sum of remaining colors that strikes our eyes. Observed and ...
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2answers
187 views

why do we see characteristic colors of alkali metals in oxidizing flame?

I am a high school student and I am a little confused in a topic, My confusion is that: We know alkali metals and their salts imparts characteristic color in oxidizing flame, for example: Lithium ...
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110 views

Why does my drierite turn bright bright blue, instead of pink?

Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry ...
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1answer
157 views

Why is HBr colorless while Br2 isn't?

Bromine ($\ce{Br2}$) has a dark reddish color. If it reacts with something like benzene, this results in the formation of Bromobenzene and $\ce{HBr}$: $$\ce{Br2 + C6H6 ->[{Cat.}]C6H5Br + HBr}$$ It ...
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1answer
590 views

Why is HgI2 a colored complex?

Why is $\ce{HgI2}$ a colored complex it has fully filled d-orbits. According to the book, one which has fully filled d-orbital has no color in transition elements. So, why is this compound colored?
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1answer
182 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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149 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 ...
4
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1answer
274 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
51 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
119 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
156 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 ...
2
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2answers
367 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
126 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
988 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
187 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 ...
2
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2answers
232 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
71 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
44 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
1k 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
44 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
218 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
90 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
44 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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0answers
262 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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