Are the products of burning carbon dioxide and water?

Question

when a candle is burning the smoke is the carbon dioxide?

you have additional info abt. products of burning?

Answer 1

The ultimate products of combustion of an organic material (a hydrocarbon) are CO2 and water.  However, most combustion is incomplete and results in the release of unburned hydrocarbons (soots and vapors).  Smoke in most cases is simply complex hydrocarbons that did not break down in the combustion-they were expelled from the fire before the chain of reaction to CO2 and water was complete.

Soots and tars from smoke tend to be more complex hydrocarbons (such as polycyclic aromatic hydrocarbons) that have higher boiling temperatures and thus do not vaporize and burn, but simply transfer through the air as suspended particulates.

The flames themselves are gases that are reacting with oxygen-in fact much of a fire takes place in the vapor phase and isn't actually the solid itself that is reacting, but consists of the gases and plasma that is expelled from the solid (or liquid) from heat energy.

Secondary components also come into play.  The presence of nitrogen, sulfur, metals, and other elements also produce compounds that are neither CO2 or water, but in the general case these things are ignored because they are not usually the primary reactants.  In some situations (combustion of things other than hydrocarbons), these elements are the primary reactants, in which case the primary output is not CO2 plus water, but other oxide compounds.

Answer 2

Ok, you've got it sdrawkcab (backwards).  Burning is the combination of an oxidizer (with a candle, oxygen) and the fuel (the wax in the wick).  It happens to release enough heat to support itself.  When the fuel runs out, th fire goes poof.  Now, adressing your question, the products of burning are not neccesarily water and carbon dioxide.  It is that way with pure methane (CH4+O2=2H2O+CO2) but with a candle for example...  Namely lots of carbon dioxide, but the smoke you see is a whole lot of pieces of solid exhaust (graphite) from the wax and wick.  Also, oxygen isn't the only oxidizer.  There is a material called silane that will burn in carbon dioxide, and two chemicals called hydrazine and nitrogen tetroxide, used in rockets, spontaneously react when they come in contact with one another (i.e., explode).  So there you have it, water and co2 aren't the only exhausts.