Why does sugar decompose under intense heat? What is the chemical explanation for this?
Answer:
Pure sugars are made up of C, H and O. For example sucrose is C12H22O11,
while glucose is C6H12O6.
If a complete combustion is done -that is the carbon completely reacts with oxygen to form the lowest energy molecule of C+O then it will form CO2, H will form H2O. So in a complete combustion, you would get nothing remaining, as the sugar will turn to CO2 and H2O (which under the conditions of complete combustion will probably vaporize)...
It melts.
The crystalline structure breaks down then the carbon part catches fire.
positive energy to electrons will free them of the lower level which they rightfully occupy.
I don't know the chemical explanation for this but, sugar when put under intense heat, turns to a gooey substance like in candy.
Sucrose loses water in a dehydration reaction to form caramel.
Caramelization (or caramelisation) involves several steps, starting with the melting of the sugar crystals, loss of water and oxidation of the sugar. These processes start at about 340 degrees F and the exact nature of the reactions depends upon the sugar and the temperature.
Common sugar contains the following molecular formula:
CH2O which is a covalent bond molecue.
Given sufficient heat energy to the point of activated complex, sugar will decompose and become 2 products: carbor (solid) + H2O (water vapor) at STP.
I detail below an actual experiment of heating sugar. It will explain the matter step by step
Place about 1/2 cup sugar into a deep nonstick pot. Place the pan on the
burner over low heat. Continuously stir the sugar as you gradually increase
the heat. Have the students observe the sugar as it is being heated and
describe what is occurring. Eventually, the sugar will melt and break down to
form carbon. Keep stirring as you discuss because the sugar melts quickly and
could start to stick and burn. Caramel is a combination of sugar and carbon.
Remove the pan from the heat when the sugar is straw colored. If you want to
make delicious candy caramel, add whipping cream and butter slowly as you
stir. Taste the caramel.
The sugar has been converted to caramel through a chemical reaction. If heated
too long, the sugar turns the dark brown color of carbon and loses all of its
sweetness - an interesting change, but not tasty. The heat causes the sugar
molecules to chemically change into a different substance, therefore it looks
and tastes differently from the original white sugar.
Every substance in the universe has a melting point, some are just extremely high. The same as every gas has a condensing point and every liquid has a freezing point. These points vary from compound to compound.
Sucrose loses water in a dehydration reaction to form caramel.
Caramelization (or caramelisation) involves several steps, starting with the melting of the sugar crystals, loss of water and oxidation of the sugar. These processes start at about 340 degrees F and the exact nature of the reactions depends upon the sugar and the temperature.
Source(s):
http://www.exploratorium.edu/cooking/can...
http://www.cnrs.fr/cnrspresse/n395/html/...
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