Since you're adding only a drop of H2SO4 to a large excess of sugar, the H2SO4 is the limiting reagent, and you'll have to measure precisely to figure out how much heat the reaction evolves. Follow these steps:
I've run this reaction many times as a vivid demonstration of an exothermic reaction. It is a violent and dangerous reaction. It releases an enormous amount of heat in a very short time, and will sometimes go off in a flash as you're mixing the ingredients. The molten salts the reaction sprays into the air can cause serious burns and permanent damage to the eyes. Please don't try this at home!
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Last Revised 08/17/15.URL: http://antoine.frostburg.edu/chem/senese/101/thermo/faq/print-dehydration-of-sugar.shtml