Mole Calculator – Convert Between Mass, Moles, and Molecular Weight

What is a Mole?

In chemistry, a mole is a fundamental unit used to express the amount of a chemical substance. It allows chemists to count particles—like atoms, molecules, or ions—by weighing them. One mole contains exactly 6.022 × 10²³ elementary entities, known as Avogadro’s number. This large number helps scientists bridge the gap between the microscopic world of atoms and the macroscopic world we interact with.

For example, 1 mole of water (H₂O) molecules contains 6.022 × 10²³ water molecules, and its mass is approximately 18 grams, which is the molar mass of water. Moles make it easier to relate mass, volume, and number of particles in chemical reactions.

How to Calculate Moles – Moles to Grams Converter

Calculating moles involves a simple but powerful formula:

Moles = Mass (g) ÷ Molar Mass (g/mol)

- Mass is the actual weight of the substance in grams.
- Molar mass is the mass of one mole of that substance, found on the periodic table (typically equal to the atomic or molecular weight).

For example, to find how many moles are in 10 grams of NaCl (sodium chloride), you divide by its molar mass (~58.44 g/mol):

Moles = 10 ÷ 58.44 ≈ 0.171 moles

Conversely, to convert moles to grams:

Mass = Moles × Molar Mass

These calculations are especially useful in stoichiometry for balancing chemical equations, determining reactant-product relationships, and conducting laboratory experiments.

FAQs

Q: What is molar mass?
A: Molar mass is the mass of one mole of a substance. It's usually measured in grams per mole (g/mol) and is equivalent to the atomic or molecular weight found on the periodic table.

Q: Why do we use moles in chemistry?
A: Moles allow chemists to measure substances in a practical and standardized way. Since atoms and molecules are so small, counting them directly isn’t feasible—moles solve this by using weight as a proxy for quantity.

Q: How can I find the molar mass of a compound?
A: Add up the atomic masses of all atoms in the compound. For example, H₂O = (2 × 1.008) + 15.999 = ~18.015 g/mol.

Q: Can I use this method for gases?
A: Yes! For gases at STP (standard temperature and pressure), you can also use volume: 1 mole = 22.4 liters for an ideal gas.