Chemistry

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Chemistry

Atomic Mass to Moles Converter.

Converts a given mass of a substance to moles using its atomic or molar mass.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Enter the mass of the substance in grams.

  2. 2

    Enter the molar mass (atomic mass) in grams per mole.

  3. 3

    Divide the mass by the molar mass to get the number of moles.

mass / molar_mass

Frequently asked questions

What is molar mass?

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It equals the atomic or molecular weight from the periodic table.

Can I use this for molecules?

Yes, use the molecular mass (sum of atomic masses) for compounds. For elements, use the atomic mass.

What if I have mass in kilograms?

Convert kilograms to grams first (1 kg = 1000 g) before using the calculator.

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Moles

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How it works

Converts a given mass of a substance to moles using its atomic or molar mass.

  1. Enter the mass of the substance in grams.
  2. Enter the molar mass (atomic mass) in grams per mole.
  3. Divide the mass by the molar mass to get the number of moles.

Formulas

The math behind this calculator, written out so you can verify the result.

Moles from mass

n = m / M

The number of moles (n) equals the mass (m) divided by the molar mass (M).

Example:

Input: m = 36.03 g, M = 18.015 g/mol

Calculation: 36.03 / 18.015

Result: 2.000 mol

Real-world use cases

Where this calculation shows up in everyday life.

Stoichiometry

Convert given masses to moles to balance chemical equations and find reactant or product amounts.

Example: Calculate moles of water from 100 g of water.

Solution preparation

Determine the amount of solute needed to make a solution of a specific molarity.

Example: How many moles of NaCl are in 58.44 g?

Lab experiments

Quickly convert measured masses to moles for quantitative analysis.

Example: Convert 12 g of carbon to moles.

Tips and common mistakes

Tips

  • Use the most accurate molar mass from the periodic table for precise results.
  • Always include units in your calculations to avoid errors.
  • For compounds, sum the atomic masses of all atoms in the formula.
  • Remember that moles are a count of particles, not a mass.

Common Mistakes to Avoid

  • Using atomic mass in amu instead of g/mol.
  • Forgetting to convert mass to grams if given in kilograms.
  • Confusing molar mass with molecular weight without units.

Assumptions and limitations

  • Use the stated inputs and units.
  • Results are estimates for planning and education.
  • Check measurements and source data before making an important decision.