Mole Calculator
Inputs
Use our Molar Mass Calculator to find this value.
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What is a Mole?
A mole is a fundamental unit in chemistry representing a specific number of particles (atoms, molecules, ions, etc.). It is defined as exactly 6.02214076 × 10²³ elementary entities, known as Avogadro's number (Nₐ).
Just as a "dozen" means 12, a "mole" means 6.022 × 10²³. This number is so large because atoms are incredibly small, and it allows chemists to work with manageable quantities.
Key Formulas
Moles from Mass:
n = m / M(n = moles, m = mass in grams, M = molar mass in g/mol)
Particles from Moles:
N = n × Nₐ(N = number of particles, Nₐ = 6.022 × 10²³/mol)
Examples
Example 1: Grams to Moles
How many moles in 36 grams of water (H₂O)?
- Molar mass of H₂O = 18.015 g/mol
- n = 36 / 18.015 = 2.0 moles
Example 2: Moles to Particles
How many molecules in 0.5 moles of CO₂?
- N = 0.5 × 6.022 × 10²³
- N = 3.011 × 10²³ molecules
Why Moles Matter
The mole concept bridges the microscopic world of atoms to the macroscopic world we can measure. It's central to stoichiometry, allowing chemists to predict how much product will form from given reactants.
Frequently Asked Questions
Why is Avogadro's number so specific?
It was originally defined as the number of atoms in 12 grams of carbon-12. In 2019, it was redefined to an exact value: 6.02214076 × 10²³.
Can I use moles for ions and electrons?
Yes! The mole applies to any countable entity: atoms, molecules, ions, electrons, photons, etc.