What happens in the above video is an exothermic reaction involving the monosaccharide and a strong acid. In this case, we witnessed the action of Sulphuric Acid + Sucrose.
When the acid is added to the sugar, the sugar transforms, expands and an effervescence of steam is observed. This reaction is clearly exothermic since the acid and the sugar were originally at room temperature.
Dehydration reactions are reactions where the H2O molecule is removed from the carbonyl compound and in balancing the equation, the acid is hydrated. This water transfer is the source of the heat in this reaction. The water and the acid create very strong hydrogen bonds, which in turn give off energy in the form of heat. When bonds break, and new bonds are formed, some bonds are easier to form than others, so often the excess energy that doesn’t go into making bonds, gives off heat as the product.
In this reaction when hydrogen and oxygen are removed from sugar, all we have left is graphite(carbon). The water escapes mostly as steam, and like most reactions, not everything is able to react, so we often have the leftover, unreacted acid evaporating with the water.
Note: This is a very dangerous experiment. Only proceed under proper supervision.
The full equation is actually pretty simple:
C12H22O11 (Sucrose) + H2SO4 (Sulphuric Acid) → 12C (Graphite) + 11H2O (Water)
Oh, if you insist on doing this experiment, kindly check your insurance policies on scientific accidents coverage, or whatever they say.