National Mole Day

Category: Science
National Mole Day in USA in 2025
Image from Pixabay. CC0

About National Mole Day

How long until National Mole Day?
National Mole Day .
Dates of National Mole Day
2026 USA Friday, October 23rdNational Mole Day
2025 USA Thursday, October 23rdNational Mole Day
2024 USA Wednesday, October 23rdNational Mole Day
2023 USA Monday, October 23rdNational Mole Day
2022 USA Sunday, October 23rdNational Mole Day
Summary
October 23, denoted 10/23 in the US, is recognized by some as Mole Day. It is an informal holiday in honor of the unit among chemists.

National Mole Day recognizes a special number in chemistry. Chemists and chemistry students mark the occasion each year on October 23.

The mole is the unit of amount in chemistry.  It provides a bridge between the atom and the macroscopic amounts of material that we work with in the laboratory.  It allows the chemist to weigh out amounts of two substances, say iron and sulfur, such that equal numbers of atoms of iron and sulfur are obtained.

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