The difference between burning and other oxidation reactions e. There are two conditions needed for a substance to burn:. The oxidation of sugar is capable of releasing a lot of heat. If you look at the nutrition information on a pack of cookies, you can see that they contain high levels of sugar and calories. However, the oxidation of sugar is quite slow, so sugar does not burn easily.
Ash serves as a catalyst accelerator in the burning reaction of sugar. A catalyst is a substance that increases the rate of a reaction, by lowering the amount of energy needed for the reaction to work. Ash is a complex mixture of substances that does not continue to burn be oxidized , which contains salts or oxides of metals. Ash from paper contains metal carbonates, such as salts of carbonic acid H2CO3. These salts or oxides act as catalysts in the sugar burning reaction.
The best catalysts are lithium salts, which are found, for example, in cigarette ash. However, paper ash contains sodium and calcium salts that can also catalyze the combustion of sugar. If sugar burns completely complete combustion then the products of the reaction are carbon dioxide and water. However, in reality, sugar tends not to burn completely and a black mass of products of incomplete oxidation of sugar result.
The black mass contains complex organic substances aldehydes, ketones, carboxylic acids and carbon. When the sugar decomposes with heat, a compound called maltol is produced, which has a characteristic "caramel" smell of burning sugar. Maltol is a naturally occurring compound that is often used as a flavor enhancer, and contains a ketone a double bond from carbon to oxygen and an alcohol a single bond from carbon to OH group. One of the most exciting and ambitious home-chemistry educational projects.
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Bigg, Matthew. February 8, Professor of chemistry. University of Arizona. Personal interview. February 11, In the following demonstration, roughly equal amounts of solid potassium chlorate and sugar in the form of finely powdered confectioner's sugar are placed in a glass jar, and mixed vigorously. Upon the addition of a drop of sulfuric acid, the chemicals react with each other, producing a tall purple flame, a lot of smoke, and a fairly spectacular explosion of the glass jar.
The same demonstration is then repeated with a closer magnification. In the second video clip, the same chemicals are combined in a Pyrex beaker, with similar results. I generally get the best results with this demo by using ordinary granulated table sugar or powdered confectioner's sugar.
Reagent grade sucrose often consists of larger granules, and requires more sulfuric acid to get the reaction to sustain itself. When using confectioner's sugar, it is especially important to get a good mixing between the two chemicals, otherwise the finely powdered sugar can smother the fire. This reaction often produces a great deal of smoke, and must either be done in a well-ventilated area, or in a working fume hood.
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