Convert ppm to moles for a solution, sample or gas using the chemical formula or molar mass, with molarity, or convert ppm to mol % and back.

Mass-based ppm needs solution density. mg/L is a separate mass-per-volume measure.

Default 1 g/mL is an approximation for dilute water solutions; enter the actual density when known.

Case-sensitive, e.g. NaCl, Ca(OH)2 or CuSO4ยท5H2O. Use Manual molar mass for ions or isotopes.

Optional settings

ppm To Moles Formula

For mass-based ppm (mg/kg), use n = C ร— V ร— ฯ / (MW ร— 1000), where ฯ is solution density in kg/L. The simplified formula below applies when ฯ โ‰ˆ 1 kg/L, or when C is entered as mass concentration in mg/L.

n = (C ร— V) / (MW ร— 1000)

Variables:

  • n is the amount of substance in moles
  • C is the concentration in parts per million (ppm), using the dilute aqueous approximation ppm โ‰ˆ mg/L
  • V is the volume of the solution (L)
  • MW is the molecular weight of the substance (g/mol)

For mass-based ppm, multiply concentration by solution volume in liters and density in kg/L to obtain solute mass in milligrams. Divide by 1000, then by molar mass in g/mol. For a weighed sample, use its total mass in kg instead of volume ร— density. Gas ppm by volume instead requires the ideal-gas relation n = (ppmv/1,000,000) ร— PV/(RT), with absolute pressure and temperature.

PPM to Moles Conversion Table (Assumes Volume = 1.00 L and Molecular Weight = 58.44 g/mol, e.g., NaCl)
Concentration (ppm) Volume (L) Molecular Weight (g/mol) Moles (mol)
0.1158.440.000001711
0.5158.440.000008556
1158.440.000017112
2158.440.000034223
5158.440.000085558
10158.440.000171116
25158.440.000427789
50158.440.000855578
75158.440.00128337
100158.440.00171116
150158.440.00256674
200158.440.00342231
250158.440.00427789
300158.440.00513347
400158.440.00684463
500158.440.00855578
750158.440.0128337
1000158.440.0171116
2000158.440.0342231
5000158.440.0855578
Assumptions: dilute aqueous solution where 1 ppm โ‰ˆ 1 mg/L. Formula used: moles = (ppm ร— Volume[L]) / (Molecular Weight[g/mol] ร— 1000). Here, Volume = 1.00 L and Molecular Weight = 58.44 g/mol (NaCl).

What is ppm To Moles?

ppm to moles is a conversion used in chemistry to estimate how many moles of a solute are present in a known amount of a mixture. Because ppm is a ratio (often a mass fraction), converting ppm to moles generally requires either the mass of the sample (w/w basis) or, for solutions, the volume and density. A common shortcut for dilute aqueous solutions is to treat 1 ppm โ‰ˆ 1 mg/L, then use the molecular weight to convert mass to moles.

How to Calculate ppm To Moles?

The following steps outline how to calculate the ppm To Moles.

  1. First, determine the concentration in parts per million (ppm). For dilute aqueous solutions, you can use the approximation 1 ppm โ‰ˆ 1 mg/L.
  2. Next, determine the volume of the solution (L).
  3. Next, determine the molecular weight of the substance (g/mol).
  4. Next, gather the formula from above: n = (C ร— V) / (MW ร— 1000).
  5. Finally, calculate the amount of substance in moles.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

concentration in parts per million (ppm) = 150

volume of the solution (L) = 0.5

molecular weight of the substance (g/mol) = 32. Using the dilute aqueous approximation, n = (150 ร— 0.5) / (32 ร— 1000) = 0.00234375 mol.