I took a piece of charcoal from my fireplace, fired it up to get it red hot, dropped it into a glass, and quickly covered the top of the glass tightly with a piece of plastic wrap. If carbon monoxide was produced, I expected each oxygen molecule to be replaced by two carbon monoxide molecules, thus increasing the volume of gas in the glass. Even if carbon dioxide was produced, one would expect mere replacement of an oxygen molecule by a carbon dioxide molecule, resulting in no increase in gas volume. The heat of the charcoal would if anything, increase the volume of gas inside the glass. What I did get is a decided depression of the plastic wrap stretched over the top of the glass, indicating a deficiency in the contained gas over what was originally present. Would anyone like to offer an explanation?