Thermal Decomposition of Ammonium Dichromate (Volcano Reaction)

(NH4)2Cr2O7 → Cr2O3 + N2 + 4H2O

Overview

Ammonium dichromate decomposes spectacularly when ignited, producing green chromium(III) oxide, nitrogen gas, and water vapor. The green fluffy chromium oxide rises like a miniature volcano as gases escape, making this one of the most dramatic chemistry demonstrations.

Participants

Role Substance Coefficient State
Product Nitrogen N 1 (g)
Product Water H₂O 4 (g)

Everyday Example

This is the famous chemical volcano demonstration performed in science classes and science fairs worldwide.

Industrial Importance

Chromium(III) oxide produced by this and related reactions is used as a green pigment (chrome green), in magnetic tape coatings, and as a polishing compound.

Properties

Type
Decomposition
Reversible
No
Energy
Exothermic
ΔH
-315.0 kJ/mol

Related Reactions

Cracking of Octane (Thermal Cracking) Decomposition of Ammonium Nitrate Decomposition of Barium Peroxide Decomposition of Calcium Carbonate (Calcination) Decomposition of Calcium Hypochlorite Decomposition of Carbonic Acid Decomposition of Hydrogen Peroxide Decomposition of Iron(II,III) Oxide (Direct Reduction) Decomposition of Nitroglycerin Decomposition of Nitrous Oxide (Laughing Gas)

Frequently Asked Questions

What is the equation for Thermal Decomposition of Ammonium Dichromate (Volcano Reaction)?
The balanced equation is: (NH₄)₂Cr₂O₇ → Cr₂O₃ + N₂ + 4H₂O.
What type of reaction is Thermal Decomposition of Ammonium Dichromate (Volcano Reaction)?
Thermal Decomposition of Ammonium Dichromate (Volcano Reaction) is a decomposition reaction.
Is Thermal Decomposition of Ammonium Dichromate (Volcano Reaction) exothermic or endothermic?
Thermal Decomposition of Ammonium Dichromate (Volcano Reaction) is exothermic (releases energy). The enthalpy change (ΔH) is -315.0 kJ/mol.