The Carbon Soufflé
Publication No. 12587
Be a chemical gourmet—whip up a carbon soufflé! Your students will be amazed as they watch a yellow solid-liquid mixture turn brown, then black, expand out of the top of the beaker and solidify. The beaker becomes extremely hot and the odor of burnt sugar will fill the room.
Sodium carbonate, Na2CO3*
Sucrose, C12H22O11, 60 g*
Sulfuric acid, concentrated, 18 M, H2SO4, 60 mL*
Beaker, borosilicate glass, 250-mL
Graduated cylinder, 100-mL
Stirring rod, glass
*Materials included in kit.
Sulfuric acid is severely corrosive to eyes, skin and other tissue; very considerable heat of dilution with water; mixing with water may cause spraying and spattering. Do not handle the carbon product with your hands; use tongs. The carbon product will contain unreacted sulfuric acid. Neutralize acid spills and the carbon product with sodium carbonate. The steam produced by the reaction can cause burns. Do not stand over the reaction vessel or inhale the steam produced. The reaction vessel will get extremely hot; allow the vessel to cool before handling. Perform this demonstration only in an efficient fume hood or a well-ventilated room. Wear chemical splash goggles, chemical-resistant apron and chemical-resistant gloves. Your carbon soufflé is not intended for consumption. It will contain corrosive sulfuric acid. Please review current Safety Data Sheets for additional safety, handling and disposal information.
Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. When the reaction is complete and the reaction vessel is cool, sprinkle the carbon product with sodium carbonate to help neutralize the remaining acid. Remove the carbon product from the reaction vessel using tongs and thoroughly rinse the carbon product under running water. Place the carbon lump inside a plastic bag. Seal the bag, then place it in the trash.
Student Worksheet PDF
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering PracticesDeveloping and using models
Using mathematics and computational thinking
Constructing explanations and designing solutions
Disciplinary Core IdeasMS-PS1.A: Structure and Properties of Matter
MS-PS1.B: Chemical Reactions
MS-PS3.A: Definitions of Energy
HS-PS1.A: Structure and Properties of Matter
HS-PS1.B: Chemical Reactions
HS-PS3.A: Definitions of Energy
HS-PS3.B: Conservation of Energy and Energy Transfer
Crosscutting ConceptsEnergy and matter
Stability and change
Systems and system models
MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
Answers to Questions
Concentrated sulfuric acid was added to a large amount of sucrose. The mixture was stirred. After several minutes, it began to bubble and “dry up.” The mixture began to expand upward, and steam was visible at the top of the beaker. After about 15 minutes the substance appeared to be completely dry, and there was a black column of carbon rising up out of the beaker.
C12H22O11(s) → 12C(s) + 11H2O
The dehydration represented the consumption of the sugar. As it occurred, energy was released in the form of heat. So much energy was released that the beaker grew hot and the carbon was forced to expand and rise out of the beaker. This shows not only the great amount of energy stored in sugar but the fact that it is all released when the food storing it is consumed.
Plants combine carbon dioxide and water in the presence of chlorophyll and sunlight to produce food and oxygen. The food is stored energy for the plant and is in the form of sugars or carbohydrates. Sugars have a molecular formula of nC•H2O (e.g., sucrose: C12H22O11, glucose: C6H12O6, arabinose: C5H10H5. This stored energy is released when the food is consumed.
Reaction 1: C12H22O11(s) → 12C(s) + 11H2O (–918.9 kJ/mol)
Shakhashiri, B. Z. Chemical Demonstrations: A Handbook for Teachers in Chemistry; University of Wisconsin: Madison, WI; 1983; Vol 1, p 77.