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I mean, when something is on fire, like an apartment building perhaps, the smoke is black, and when someone is smoking a ciggarette, the smoke is white. So what makes smoke different colors?

2006-10-13 09:47:05 · 9 answers · asked by Valkyrie 4 in Science & Mathematics Chemistry

9 answers

My guess is that it will vary with the material the smoke particle are made of and in some circumstances the thickness of the smoke cloud (if it is dense and large against a bright sky it may appear dark whereas if less dense and with light behind the viewer it may appear white). However smoke is invariably black when unburnt hydrocarbons (tar,soot) are present due to incomplete combustion (an oil, plastic or rubber fire). When combustion is more complete the smoke may be particles of white ash (a cigarette or wood fire)

2006-10-13 10:03:48 · answer #1 · answered by Robert A 5 · 0 0

The color also depends on how efficient is the burning and the quality of the fuel.

The less efficient the burning the more carbon will not be completely converted to CO2 and will make the smoke black.

Also if you look at a candle you have different regions in the flame with different colors. These colors are associated with different temperatures.

2006-10-13 17:15:08 · answer #2 · answered by Dr. J. 6 · 0 0

Incomplete combustion. If a substance completely burns, carbon is produced and is removed from the site of combustion by the other hot gases rising from the fire, i.e. water vapor, nitrogen gas, or plain 'ole air.

If a substance doesn't completely burn, due to insufficient oxygen or insufficient heat, the airborne particles that you see as smoke are some other color. The color of the smoke is dependent on the material being burned.

2006-10-13 11:35:45 · answer #3 · answered by jogimo2 3 · 0 0

that is due to IMCOMPLETE COMBUSTION. many carbon-base things can burn to produce CO2 and H20 or CO and H2. While other substances that are burnt contain other organic and inorganic chemicals, such as NH3-based, P4, S6, Mg, Ca.... the colors shows the chemical composition, reaction completion, chemical kineitcs, and chemical equilibrium.

color is the refraction of the frequency and KE of the photon, which is absorbed and emitted by the smoke

2006-10-13 13:52:57 · answer #4 · answered by cool nerd 4 · 0 0

Call Car Talk

2016-05-21 23:34:55 · answer #5 · answered by Jo-ann 4 · 0 0

different chamicals. like anything different chamicals make different colours. also there is less smoke from a cigarete than from a building so it is not as dense and therefore lighter.

2006-10-13 09:49:09 · answer #6 · answered by ui6fu6yujt c 2 · 0 0

Most elements burn in different colors. Like they put different things in fireworks so they will burn in different colors

2006-10-13 09:49:54 · answer #7 · answered by abel g 2 · 0 0

Chemical composition
The composition of smoke depends on the nature of the burning fuel and the conditions of combustion.

Fires with high availability of oxygen burn in high temperature and with small amount of smoke produced; the particles are mostly composed of ash, or in large temperature differences, of condensed aerosol of water. High temperature also leads to production of nitrogen oxides. Sulfur content yields sulfur dioxide. Carbon and hydrogen get completely oxidized to carbon dioxide and water.

Fires burning with lack of oxygen produce significantly wider palette of compounds, many of them toxic. Partial oxidation of carbon produces carbon monoxide, nitrogen-containing materials can yield hydrogen cyanide, ammonia, and nitrogen oxides. Content of chlorine (eg. in polyvinyl chloride) or other halogens may lead to production of eg. hydrogen chloride, phosgene, dioxin, and chloromethane, bromomethane and other halocarbons. Pyrolysis of the burning material also results in production of large amount of hydrocarbons, both aliphatic (methane, ethane, ethylene, acetylene) and aromatic (benzene and its derivates, polycyclic aromatic hydrocarbons; eg. benzo[a]pyrene, studied as a cancerogen, or retene), terpenes. Heterocyclic compounds may be also present. Heavier hydrocarbons may condense as tar. Presence of sulfur can lead to formation of eg. hydrogen sulfide, carbonyl sulfide, sulfur dioxide, carbon disulfide, and thiols; especially thiols tend to get adsorbed on surfaces and produce lingering odor even long after the fire. Partial oxidation of the released hydrocarbons yields in a wide palette of other compounds: aldehydes (eg. formaldehyde, acrolein, and furfural), ketones, alcohols (often aromatic, eg. phenol, guaiacol, syringol, catechol, and cresols), carboxylic acids (formic acid, acetic acid, etc.).

The visible particles in such smokes are most commonly composed of carbon (soot). Other particulates may be composed of drops of condensed tar, or solid particles of ash. Content of metals yields particles of metal oxides. Particles of inorganic salts may also be formed, eg. ammonium sulfate, ammonium nitrate. Many organic compounds, typically the aromatic hydrocarbons, may be also adsorbed on the surface of the solid particles.

Smoke emissions may contain characteristic trace elements. Vanadium is present in emissions from oil fired power plants and refineries; oil plants also emit some nickel. Coal combustion produces emissions containing selenium, arsenic, chromium, cobalt, copper, and aluminium.

Some components of smoke are characteristic for the combustion source. Guaiacol and its derivates are products of pyrolysis of lignin and are characteristic for wood smoke; other markers are syringol and derivates, and other methoxy phenols. Retene, a product of pyrolysis of conifer trees, is an indicator of forest fires. Levoglucosan is a pyrolysis product of cellulose. Hardwood vs softwood smokes differ in the ratio of guaiacols/syringols. Markers for vehicle exhaust include polycyclic aromatic hydrocarbons, hopanes, steranes, and specific nitroarenes (eg. 1-nitropyrene). The ratio of hopanes and steranes to elemental carbon can be used to distinguish between emissions of gasoline and diesel engines. [1]

You could get more information from the link below...

2006-10-14 00:24:04 · answer #8 · answered by catzpaw 6 · 0 0

chemicals and temperature

2006-10-13 09:48:58 · answer #9 · answered by jugglaman 4 · 1 0

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