H

Hydrogen

H Elements CAS 1333-74-0
Quick Reference
Formula / NotationH
CAS Number1333-74-0
Molecular Weight1.008
Also Known AsH₂, dihydrogen, hydrogen gas, protium (most common isotope)
CategoryElements

What is Hydrogen?

Hydrogen is the lightest and most abundant element in the universe, making up about 75% of all normal matter by mass. It is a colourless, odourless, highly flammable diatomic gas at standard conditions.

Formula & Notation

H

Other Names / Synonyms: H₂, dihydrogen, hydrogen gas, protium (most common isotope)

Properties & Characteristics

Appearance: colourless gas. Melting point: −259.16 °C. Boiling point: −252.88 °C. Density (gas): 0.08988 g/L.

Uses & Applications

Ammonia synthesis (Haber process). Petroleum refining. Fuel cells. Rocket propellant. Reducing agent in metallurgy.

Safety Information

Extremely flammable (4–75% range in air). Colourless and odourless. Cryogenic liquid causes frostbite.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Hydrogen
Formula H
CAS Number 1333-74-0
Molecular Weight 1.008
Category Elements
Synonyms H₂, dihydrogen, hydrogen gas, protium (most common isotope)

Frequently Asked Questions

Hydrogen is the lightest and most abundant element in the universe, making up about 75% of all normal matter by mass. It is a colourless, odourless, highly flammable diatomic gas at standard conditions.

More "H" Terms

View all "H" terms →
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z