Mole Calculator
Convert mass to moles instantly using molecular weight
Calculate Moles
Formula:
n = m / M
Where n = number of moles, m = mass (g), M = molecular weight (g/mol)
Example: 18.0
Example: 18.015 (for H₂O)
Result:
Frequently Asked Questions
What is a mole in chemistry?
A mole is a unit that represents 6.022 × 10²³ particles (atoms, molecules, ions, etc.). It's Avogadro's number and is used to count very large numbers of tiny particles. One mole of any substance contains the same number of entities.
How do you calculate moles from mass?
To calculate moles from mass, divide the mass in grams by the molecular weight (molar mass) in g/mol. The formula is: moles = mass / molecular weight. For example, 36 grams of water (MW = 18) equals 2 moles.
What is molecular weight?
Molecular weight (or molar mass) is the mass of one mole of a substance, expressed in grams per mole (g/mol). It's calculated by adding up the atomic weights of all atoms in a molecule. For H₂O: (2 × 1.008) + 16.00 = 18.016 g/mol.
How do you convert moles back to grams?
To convert moles to grams, multiply the number of moles by the molecular weight: mass (g) = moles × molecular weight (g/mol). For example, 0.5 moles of NaCl (MW = 58.44) equals 29.22 grams.
What is Avogadro's number?
Avogadro's number is 6.022 × 10²³, which is the number of particles (atoms, molecules, etc.) in one mole of any substance. It's named after scientist Amedeo Avogadro and is fundamental to chemistry calculations.
Why do we use moles instead of counting atoms?
Atoms and molecules are too small and numerous to count individually. Moles allow us to work with manageable numbers in the lab while still accounting for the enormous number of particles involved in chemical reactions.