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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Why Green Solution After Putting Bismuth Antimony in Nitrogen Acid
I am in a physics lab studying dislocation, and we submerged a bismuth antimony sample in nitrogen acid (about 50% concentration, if I remembered it right) as the first step to etch it. There were ...
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Silica gel reheating (orange)
I am a non-chemist looking for some advice! I am an archaeologist and am currently using moisture-indicating silica gel (orange) to dry out some metal finds from our excavations. I have reheated ...
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Color of coordination compounds
My book(Page $259$ section $9.5.5$) says that the color mainly comes from absorption of light in the coordination compound:
The color is complementary of the wavelength it absorbs , the wavelength ...
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Can a colorant be mixed into zirconia powder?
I’m wanting to color zirconium dioxide into beads after it is fired but I would like to get more colors than just white and the high temperature black oxide. Can I mix other metal oxides to zirconium ...
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Reason behind paramagnetic substances having color
I've read in many books that paramagnetic substances are coloured while diamagnetic substances are colourless (yes there are some exceptions too). But nowhere i could find a reason for this phenomenon....
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What is that substance coming from tractor tire?
I have old tractor with Bridgestone tires. When I press a clean white tissue against the tire, a black spot show on the tissue. Is that substance carbon black and it’s harmful to soil?
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Why does color of substances not disappear after some time?
Some compounds are colored due to HOMO-LUMO transition. We see the complimentary color to the frequency which the electron absorbs to get the high molecular orbital. But after some the electron should ...
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Why hot iron turns from red to white and then blue? [closed]
While reading structure of atom chapter no. 2 from ncert class 11th chemistry part 1 book, I got a doubt. In the book it says on page 40 that:
Hot objects emit electromagnetic radiations over a wide ...
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Colour of CuO and CuCl2 [closed]
Colour of $\ce{Cu^2+}$ is blue.
Then why is the colour of $\ce{CuCl2}$ green and $\ce{CuO}$ black? Because both of these compounds have $\ce{Cu^2+}$.
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Color change when heating organic compound
I did just attend a lab class where I should synthesize 3,6-dibromo- N-propylcarbazole from N-propylcarbazole by bromination. Once, the bromination was over the color of the reaction content was ...
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Resazurin not turning pink
I want to add resazurin to my media as an anaerobic indicator.
To my understanding, the resazurin is blue when first added to the media, then turns pink after autoclaving, and finally it turns ...
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Detection of Nitrogen and Sulfur in Lassaigne's Test
In Lassaigne's test for the detection of nitrogen and/or sulfur in organic compounds, we prepare Lassaigne's extract. In this extract, NaCN is formed if nitrogen is present, and $\ce{Na2S}$ is formed ...
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Colored inorganic liquids: why is SCl2 red, and S2Cl2 orange?
Those do not involve d orbitals, so there is no crystal field theory or ligand theory. Do we have a name of study that only involves p orbitals? Since I think molecular theory is for all s p d f ...
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Colour properties of nickel complexes
According to Crystal Field theory (CFT), complexes with stronger ligands must absorb light with higher frequency hence would transmit corresponding complementary colour.
The colour of $(\ce{[Ni(H2O)2(...
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Make Yellow rust on cast iron
I am an artist looking for a chemist to collaborate with. I an trying to create Yellow Rust on an old french cast iron fireplace insert.
Aside from vinegar, salt and hydrogen peroxide (that result in ...
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Colour changing Lipstick
I have bought a colour changing lipstick with the colour Phloxine B.(Other ingredients, see below...)
Normally this colour changes to pink at pH 5.
So this means on skin it changes its colour because ...
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white vs light pink color of MgO
Recently I ordered some high purity MgO, which is light pink in color. However, the old powder I was using was white. MSDS also suggests that it should be white. Can anyone explain the reason of two ...
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Why wavelength of Rubidium flame test(red violet) is more than Lithium(crimson red)
My teacher show this table from my book
Here, you can see Red violet wavelength is more than Lithium, which is against order of visible light which increase according to acronym 'VIBGYOR'
According ...
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Why sulfur dissolved in ethylenediamine turns green?
Davis, R. E., & Nakshbendi, H. F. (1962). Sulfur in Amine Solvents. Journal of the American Chemical Society, 84(11), 2085–2090. doi:10.1021/ja00870a017
I've also done this experiment. But what ...
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Why does benzaldehyde turn yellow?
We used benzaldehyde for a demonstration of the Cannizzaro reaction in school, but the liquid we used appeared visibly yellow, as opposed to the colourless liquid described by Wikipedia.
A few reasons ...
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Could a beach have green or blue sand due to a nearby copper deposit? How poisonous would such a beach be? [closed]
I am in the midst of a world building project and am wondering about green sand from copper oxide/patina material. The material could either be washed into the water from a nearby land deposit or be ...
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Why are iodine precipitates yellow? [closed]
Why do iodine precipitates appear yellow? Learning about precipitates I noticed that compounds like Lead Iodide and Silver Iodide are yellow.
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Colour of ferrous hydroxide crystal
My chemistry teacher said that pure $\ce{Fe(OH)2}$ is a "white" crystalline solid in anaerobic environments, and acquires the usual green tinge, the colour of $\ce{Fe(II)}$, when in contact ...
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Intense purple colour of litmus paper in contact with calcium oxide
When conducting an experiment to identify some common chemicals, I tested
crystal/powder samples of the chemicals with moist litmus paper. When I put a piece of blue paper on some $\ce{CaO}$ powder, ...
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Why is hexacyanoferrate(II) coloured whereas tetrachlorocadmiate(II) is not, even though both lack unpaired electrons?
$\ce{K4[Fe(CN)6]}$ is coloured whereas $\ce{Na2[CdCl4]}$ is not. Even Laporte selection rule would suggest the tetrahedral cadmium complex to have a higher intensity of colour than the octahedral iron ...
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Why are vapours of xenon hexafluoride coloured?
According to Wikipedia,
[...] It is a colorless solid that readily sublimes into intensely yellow vapors.
It is clear from the above statement that $\ce{XeF6}$ is colourless in solid form. But why ...
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Why do the links in a plastic chain become different colors?
I have a plastic chain, about 5 meters long, sitting between two wooden posts. The link has 1 meter long sections of alternating white/red links. It's been sitting there for 2 years, and the once red ...
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How does pressure affect the color of reaction medium with equimolar amounts or reactants and products at equilibrium?
Chlorine gas is pale yellow-green, and both hydrogen and hydrogen chloride are colorless gases. According to the Le Chatelier's principle, the change in pressure will not affect the following ...
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Why is AgOH brown when silver(I) ions are colorless?
As Wikipedia states, $\ce{Ag+}$ ions are colorless in solution: https://en.wikipedia.org/wiki/Color_of_chemicals
Compounds that I know of containing $\ce{OH-}$ are also colorless or white (such as $\...
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Does nitrous oxide decolorize potassium permanganate?
My teacher says that nitrous oxide can't form any complex with manganese in aqueous solution, so it can't be oxidised. However, shouldn't it get oxidised as it is present in the intermediate oxidation ...
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How can I produce Red Iron oxide with electrolysis
I am producing Iron Oxide with the intention of using it for pigmentation. My attempts so far have been to use electrolysis. My first attempt I used Borax as an electrolyte and a 12 volt adapter with ...
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Ferrocene's band gap is supposed to make it colorless but it isn't. Why is it so?
Wang and Islam [1] state that the ferrocene molecule's band gap, i.e. the HOMO-LUMO gap at the Kohn-Sham level, is 5.03 eV, which corresponds to an absorption wavelength of at most 240 nm.
So, ...
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PVP-iodine and octenidine can stain skin purple, does the reaction create iodine radicals?
In this paper it is mentioned that
... octenidine can release iodine radicals from the
PVP complex, resulting in a tissue irritation as well as
strong brown to violet discolouration in the border ...
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Why is NMP developing a yellow color after distillation?
I got an aqueous mother liquor of N-methyl-2-pyrrolidone (NMP) from some reaction I was running and when I redistilled it under vacuum, it came out colorless but turned yellow the next day. I am ...
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Colour of diamagnetic compounds using Crystal Field Theory
I know that the colour in coordination compounds can be explained by CFT in terms of d-d transitions.
Are d-d transitions possible in diamagnetic complexes?
Why does $\ce{[Co(NH3)6]^3+}$ show colour?
...
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Why is instant coffee powder not as dark as the coffee resulting from it?
Instant coffee granules generally are of a light brown colour, while coffee made from it is a deep black. Pigments are far more concentrated in the dry form, to add water is to dilute them. Still, ...
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Simple bistable and reversible electrochromic reaction in solution
I'm not a chemist and I'm looking for a simple bistable and reversible electrochemical reaction that changes color, specifically:
A liquid in a glass with two electrodes that when a voltage is ...
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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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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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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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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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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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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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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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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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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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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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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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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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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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