How can oxydation(addition of oxygen) of a material give back its colour after it has been bleached?
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What specifically are you talking about, because I've never observed such a phenomenon.  I spent a year and a half working with sulfur dioxide and debugging a device designed to create it, and I've seen how it bleaches, and I don't know of any reversion to an "unbleached" state as you mention.\n\nReduction is NOT the removal of oxygen, and sulfur dioxide doesn't reduce anything.  Sulfur dioxide is an oxidizer.  Oxidation is the process by which electrons are removed from a reducer.  Generally, the way that this destroys color is by breaking the conjugated bonds in organic molecules that absorb color.\n\nIn some cases, color can be the result of the oxidation state of a metalic atom.  In an ionic state, it might have color, while it might become colorless when it is reduced.  Oxygen in the atmosphere could certainly make a metal atom become colorful (it turns copper green, iron red, etc).  But I can't see how sulfur dioxide could function as a reducing agent.
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Bleach,bleach bleach.
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BLEACH\nBleach helps keep white clothes white and helps remove many stains. Measure bleach carefully, as too much bleach will damage clothes.\n\nChlorine Bleach\nChlorine bleach comes in liquid and powdered forms. A variety of house and name brands are available. All liquid bleaches contain approximately 5% active ingredient. Select the product that provides the best results.\n\nLiquid chlorine bleaches are usually less expensive than powdered forms. They kill germs, too. Some fabrics and finishes are damaged or discolored by chlorine bleaches, so read the labels on clothes and bleach containers before using chlorine bleach.\n\nIron deposits in water will interact with chlorine bleach and make rust stains on clothes. Chlorine bleach also makes some yellow stains worse and may make holes in fabric.\n\nChlorine bleaches may be used on:\n\nDish towels           Bath towels \nSheets                   Color-fast prints \nPillowcases           Tablecloths \nWhite socks          T-shirts and undershirts \nOther chlorine bleach-safe items\n\nCaution: Do not use chlorine bleach on silk, wool, spandex stretch fabrics, blends of these fibers, or fabrics with certain dyes and finishes. Check clothes labels and hang-tags to determine if they can be safely bleached.\n\nHow to Use Liquid Chlorine Bleach\nFor most top-loading washing machines, do not use more than 1 cup of liquid chlorine bleach. If the machine is extra large, use 1-1/4 cup of bleach. For front-loading machines, do not use more than 1/2 cup liquid bleach. For hand washing, do not use more than 1 tablespoon of bleach per gallon of water.\n\nMix the bleach with lots of water before mixing with soapy wash water. Otherwise the bleach may make holes in the fabrics.\n\nRinse clothes well to remove the bleach, as it may weaken the clothes if it stays in them.\n\nOxygen Bleach\nMost oxygen bleaches are powders. They can be safely used on any clothes that need bleaching and are safe for all fabrics, fabric finishes, and colored fabrics. Look for the words, "Safe for all fabrics" on the package. A variety of oxygen bleach products are available.\n\nHow to Use Oxygen Bleach\n- Add oxygen bleach to the wash water. \n- Most oxygen bleaches work best in hot water. \n- Follow directions on the package. \n- Rinse the clothes well. \n- For best results, use oxygen bleach each time the items are washed.
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Bleach is an oxidizing agent which removes the color. You can't remove it once it has taken the color out but you can dye the area. Go to a carpet store. They should be able to assist you with matching the color..with swatches or carpet pieces. Good luck.
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usually metals are used to color the compounds. Look at glass blowing webites its similar in the construction. There are also salts that can be used.
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Bleach\nsodium hyporchlorite has HCL in it\nMuritic acid
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For badly stained clothes I use Oxyclean; you may have to soak the garment for several days in a stronger than recommended solution.
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Sodium hypochlorite is a strong oxidizer. In water, it partially splits into the sodium cation Na+ and the hypochlorite anion ClO−, while a substantial portion hydrolyses into sodium hydroxide and hypochlorous acid. The oxidizing power of the latter and of the hypochlorite anion cause the bleaching effect.\nyea you're right infact soduim hypochlorite is callec bleach.despite the fact that there are other bleaching agents.
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fisrt purple then back to blue \n\nthe chemical reactions that occur durring oxygen deporvation would be the same causing blood vessels to flush (turning us red- them blue) then upon oxygen deprovation in the bloodstream the hemoglobin would loose its red appearance giving the blue tint (so blue skin would stay blue)\n\nThat is of course assuming smurfs where REAL !! and had simalar physiology to existing life forms
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Br2 reacts with the double bond of an alkene.    The double bond disappears and the carbon atoms of the former double bond are now bonded to a Br atom.  Since Br2 is broken apart, then it no longer has the color.
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Cloth, especially made of natural fibers that have been dyed, will always fade.  This is what I found on the website noted below:\n\n"You’ll find that over time, some clothes fade or change colour more quickly than others. It all depends on the type of dye used to colour them. Ordinary dyes such as natural dyes just stick to the molecules that make up the material and so don’t last as long. But the newest class of dye, ‘reactive’ dyes such as azo dyes, become part of the molecules that make up the material and therefore are remarkably colour fast.\n\nCertain factors such as bleach, which can sometimes be found in washing powder, sunlight, artificial light, or even atmospheric gases all speed up the rate your clothes fade. Unfortunately this fading is permanent and the only way you will get your clothes looking blacker than black again is to re-dye them."
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By making glycerine a low pH, you make it more acidic. Bleaching solutions are more stable at a low pH.\n\n"bleaching products include glycerine, sodium stannate, flavorings, and phosphoric or citric\nacid. Because bleaching solutions are more stable at a lower pH, phosphoric or citric acid\nis added to lower their pH. Commonly, home bleaching products have a pH range of from\n5 to 7, but some products vary from 3 to 8.5 due to variations in quality control. It is\nimportant to note that the somewhat low pH of bleaching products is quickly neutralized\nwhen the solution comes into contact with saliva."
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Deterioration is due to photodegradation of polymer, the main constituent of the paint. The bleaching of color of the paint is due to photo/thermal oxidation of the pigment.
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Many materials can react with ozone to form oxygen as a by-product.  Most all are reducing agents.  A more definitive answer rests on how you are using the term "element".  If you are using it the periodic table sense then your answer would include many of the metals capable of being oxidized.
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The color of a substance is based on the light that it emits, typically after absorbing photons from an external source.  The movement of electrons from one energy level to another is what is typically responsible for the light we see.  If you ionize a substance, you affect the energy levels that are available to an electron to be excited to, or relax down to, and hence you affect its color.
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lol, last minute lab write ups. afaik enzymes dont change colour, as they are not supposed to change so id bet there is something else that the enzyme works on. better put up the other reagents to get a better answer
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It very well may be surface only discoloration...buff an area and see.Just because it blued a little is no reason to think it is contaminated deeper. The blueing is oxadation due to the heat.