Publication No. 12320
The following experiment demonstrates an example of an exothermic reaction. It can also be used as an example of a chemical change.
The purpose of this experiment is to demonstrate decomposition of chemicals by combustion.
Isopropyl alcohol, 30 mL*
Sodium bicarbonate, 1 g*
Sucrose, 6 g*
Butane safety lighter
Container vial, small*
Evaporating dish, 80 mL*
*Materials included in kit.
Isopropyl alcohol is a flammable liquid and a fire hazard; keep away from all flames, sparks, and heat sources. Isopropyl alcohol is also slightly toxic by ingestion and inhalation [LD50: 5045 mg/kg]. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Wash hands thoroughly with soap and water before leaving the laboratory. Follow all laboratory safety guidelines. 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. The solid products of this reaction may be disposed via Flinn disposal method #26a. The sand can be reused or disposed via Flinn disposal method #26a.
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering PracticesDeveloping and using models
Obtaining, evaluation, and communicating information
Disciplinary Core IdeasMS-PS1.A: Structure and Properties of Matter
MS-PS1.B: Chemical Reactions
HS-PS1.A: Structure and Properties of Matter
Crosscutting ConceptsEnergy and matter
Structure and function
Cause and effect
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.
The “snake” consists of mainly carbon that comes from the heated sugar, but which was not volatilized in the flame. The carbon is what makes the snake black. There is also Na2CO3 in the snake, which results from the decomposition of the baking soda when heated. The sugar and baking soda snake proceeds according to the following chemical reactions, where sodium bicarbonate breaks down into sodium carbonate, water vapor and carbon dioxide gas; while burning the sugar in oxygen produces water vapor and carbon dioxides gas. The pressure created from the release of the carbon dioxide gas causes the snake to grow. The snake gets its black appearance due to the sugar being caramelized by the heat.
C12H22O11(s) + 12O2(g) → 12CO2(g) + 11H2O(g)
C12H22O11(s) → 12C(s) + 11H2O(g)
2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
C3H7OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g)