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yes I agree this is the macroscopic level but what happens at the molecular level
I was taught that water robs fire of oxygen and creates steam
If you ever have a fire in a chimney, you might be able to put it out by putting a cup of water into the fire. The steam going up the chimney might put the fire out.
Quote from: Geezer on 28/03/2010 17:18:36If you ever have a fire in a chimney, you might be able to put it out by putting a cup of water into the fire. The steam going up the chimney might put the fire out.Why would steam put a fire out? Surely once it's undergone it's phase change it can absorb no more heat. Are you suggesting that the proportion of of steam in the air would be so great that the fire is effectively asphyxiated?By the way, we were always taught in school that water turns to steam at 100c (under normal atmospheric pressure) and so steam is also always 100c. But is that really so? If you put water on a fire that may be 1,000c, for instance, will the water vapour continue to be heated until it is out of the vicinity of the heat source and therefore reach a greater temperature?
Imagine we lived on a really cold planet and, rather than discussing water we were talking about nitrogen.Would you say "The only way to make (steam) nitrogen hotter than (100C) 77K is to increase it's pressure"?look back to this planet and we have no difficulty at all getting nitrogen hotter than 77K. Why would water be different?
Mg + H2O --> MgO +H2Oh, I forgot to mention, an oxyhydrogen flame burns at something like 2500C. What do you think it produces, and at what temperature?