Thermal Decomposition of Mercury(II) Oxide

2HgO → 2Hg + O2

Overview

Mercury(II) oxide decomposes when heated to about 500 C into mercury metal and oxygen gas. This reaction is historically significant as it was used by Joseph Priestley in 1774 to discover oxygen. The red powder turns into shiny mercury droplets when heated.

Participants

Role Substance Coefficient State
Product Oxygen O 1 (g)
Product Mercury Hg 2 (l)

Everyday Example

This reaction is primarily of historical significance, demonstrating a fundamental chemical principle in the discovery of oxygen.

Industrial Importance

While no longer used industrially, this reaction was crucial to the development of modern chemistry and our understanding of elements and compounds.

Properties

Type
Decomposition
Reversible
Yes
Energy
Endothermic
ΔH
181.6 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 Mercury(II) Oxide?
The balanced equation is: 2HgO → 2Hg + O₂.
What type of reaction is Thermal Decomposition of Mercury(II) Oxide?
Thermal Decomposition of Mercury(II) Oxide is a decomposition reaction. It is reversible under certain conditions.
Is Thermal Decomposition of Mercury(II) Oxide exothermic or endothermic?
Thermal Decomposition of Mercury(II) Oxide is endothermic (absorbs energy). The enthalpy change (ΔH) is 181.6 kJ/mol.