Carbon Souffle
(Decomposition of Sucrose)
Science Kit - Teacher's Guide
SED 695B
Author: Dean Papadakis
Overview: This demonstration is the
Decomposition of Sucrose. First we will
look at the definition of the term
“CARBOHYDRATE”, by examining the
formula for sucrose. Next we will
perform the experiment and make
observations. The balanced chemical
equation for the reaction can be written
and examined. The reaction can be
repeated by replacing the granulated sugar
with powdered sugar, so that you can
investigate the affect of changing the
particle size and therefore, concentration,
on the rate of the reaction.
Set up of the materials for the Carbon Souffle
C12H22O11(s)  12 C(s) + 11 H2O(g) + NRG
The general formula for the sucrose is Cx(H2O)y
H2SO4 (aq) is the dehydrating agent that catalyzes this
decomposition reaction.
Since the energy term is a product, this is an
EXOthermic reaction.
EXPERIMENT SUMMARY
Topics:
 Organic Chemistry & Biochemistry

Conservation of Matter & Stoichiometry

Reaction Rates
Standards:
The conservation of atoms in chemical reactions leads to the
principle of conservation of matter and the ability to calculate the
mass of products and reactants. As a basis for understanding this
concept:
Students know how to describe chemical reactions by writing balanced
equations.
Chemical reaction rates depend on factors that influence the
frequency of collision of reactant molecules. As a basis for
understanding this concept:
Students know how reaction rates depend on such factors as
concentration, temperature, and pressure. Students know the role a
catalyst plays in increasing the reaction rate.
In this demonstration, many terms and ideas
are presented. The first one is the definition of
the term, carbohydrate. This term is
describing the fact that sugar contains two
substances, which are the element carbon and
the compound water. Since people have an
idea what carbon looks like, as in the form of
charcoal, they will recognize one of the
products of this decomposition as the element
carbon. When the other product, water is
formed, it is formed as a gas due to the large
amount of heat that is produced, and the
water can be seen as STEAM.
Another important idea is that of a
dehydrating agent, such as sulfuric acid.
The sulfuric acid acts really like a catalyst to
help break apart or decompose the compound,
sucrose, into the elements that make it.
After the reaction proceeds, the plastic cup
melts and this is evidence for the
exothermic nature of the reaction.
After the experiment is performed,
it may be repeated by replacing the granulated
sugar with powdered sugar. This will
investigate how changing the surface area will
The bonding characteristics of carbon allow the formation of many affect the rate of the reaction.
different organic molecules of varied sizes, shapes, and chemical
properties and provide the biochemical basis of life. As a basis for The materials in this experiment can be
understanding this concept:
obtained from the store and will be much less
Students know the bonding characteristics of carbon that result in the expensive than the $35 asked from Flinn
formation of a large variety of structures ranging from simple
Scientific.
hydrocarbons to complex polymers and biological molecules.
Procedure:
Do this demonstration in a well-ventilated area or in a fume hood. Half-fill a plastic cup with granulated table sugar.
Place a glass stirring rod into the sugar. Add 5-10 mL of concentrated sulfuric acid to the sugar in the cup and begin
stirring. After a moment or two, the reaction will proceed very quickly. When the reaction is complete, you should wash
the cup and container in tap water, to remove any acid that remains. After viewing the products, they can be placed in a
plastic bag and discarded. You may repeat the experiment using powdered sugar instead of granulated sugar, so that you
can investigate how changing the surface area of a reactant affects the speed of the reaction.
Questions:
(1) What role does the sulfuric acid play?
(2) What is the general formula for a carbohydrate?
(3) What observations lead you to determine whether the reaction is endothermic or exothermic?
(4) What do you think was the composition of the gas that was produced?
(5) How would changing the particle size of the sugar from granulated to powdered, affect the rate of the reaction?
Applications to everyday life:
Since sucrose is a common substance (table sugar), examining its properties can be a useful thing. Additionally, the role
of the concentrated sulfuric acid, is as a “dehydrating agent”. One useful application of this is in the use of drain opener
which uses concentrated sulfuric acid as a means of decomposing paper items such as toilet paper that causes a drain pipe
to get clogged up. By understanding the role of the sulfuric acid in this demonstration, its role as a drain opener can be
better understood.
References & Links: http://www.flinnsci.com/