|MadSci Network: Chemistry|
Hello! To answer your second question (about the temperature of a candle flame), check out the most recent chemistry archives section, where that exact question was asked a few weeks ago. If you have further questions about his response, I'd suggest emailing him. As for your question about the propane and/or butane flame...the answer is that they are hot. If you combust either chemical in air (approx 20% oxygen, 79% nitrogen and 1% argon, where oxygen is the material which affects the flame's temperature), you "oxidize" the material. What is happening is that you are turning molecules with a lot of energy in their bonds (propane or butane) into ones with less energy in their bonds (carbon dioxide and water). As such, the excess energy is given off in the flame. Hydrocarbons (molecules containing both the elements hydrogen and carbon only) are generally full of energy and make good fuels (because of the large amount of energy that can be liberated). If you don't have oxygen present, you don't get as much energy liberated, because your products (probably hydrogen gas and carbon soot) aren't as low in energy. I don't know for sure (although the person that answered the candle question probably does), but I'd say that the flame temperature is probably about 2500 degrees Fahrenheit. You'd never attain that temperature, though. The reason you can't heat an object up to that temperature is that air cools things. As you are trying to get a pan or pot to that temperature, collisions with air molecules remove heat from the object being heated, so that there is a balance between heating and cooling (that's why a hot pot rapidly cools when the flame is removed). Additionally, if there is something in the pot (like water, for example), then the temperature of the system (pot and water) won't go above the boiling point of the water until all of the water is boiled away (that is, all energy goes into vaporizing the water, and not in raising the temperature of the system). I know that I didn't say a lot about the temperature of the flame per se, but I think that the background info is useful. Please feel free to email me if you have further questions email@example.com Best Regards, Mike
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