Solubility Converter
Convert solubility and concentration units between mass/volume and molar forms.
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What it does
The solubility converter changes solubility and concentration values between mass-per-volume units and molar units. It helps chemists, formulation scientists, and students compare literature data, prepare stock solutions, and express solubility in the most useful form.
How it works
The converter handles two families of units. Mass/volume units include g/L, mg/mL, ug/mL, percent w/v, and ppm. Molar units include M, mM, uM, and nM. Converting between the two families requires the solute molar mass through the relation M = m / (MW × V), so the amount of substance in moles equals mass divided by molecular weight. A 1 percent w/v solution means 1 g per 100 mL, or 10 g/L. For dilute aqueous solutions, 1 ppm is approximately 1 mg/L. Molarity is obtained from a mass concentration by dividing by the molar mass: M = (g/L) / (g/mol).
Worked example
Sodium chloride has a molar mass of 58.44 g/mol. Its solubility is about 360 g/L at 25 C. In molar terms this is 360 g/L divided by 58.44 g/mol = 6.16 M. Conversely, a 0.1 M solution of glucose (MW 180.16 g/mol) is 0.1 mol/L × 180.16 g/mol = 18.0 g/L, or 18.0 mg/mL. A 10 ppm solution of a pollutant in water is about 10 mg/L, and for a compound of MW 150 g/mol this equals 10/150 = 0.0667 mM.
When to use it
Use it to convert a published solubility given in mg/mL into molarity for reaction planning. Use it to switch between ppm and mg/L when reporting environmental or aqueous concentrations. Use it to turn a percent w/v formulation into a molar stock concentration.
FAQ
- How do I convert mg/mL to molarity?
- Convert mg/mL to g/L (mg/mL equals g/L directly), then divide by the molar mass. For example 18 mg/mL of glucose (180.16 g/mol) is 18 g/L divided by 180.16 = 0.10 M.
- What does 1 ppm mean in water?
- For dilute aqueous solutions, 1 ppm is approximately 1 mg/L because 1 L of water weighs about 1 kg. It is a mass ratio of one part per million by mass.
- What is percent w/v and how do I convert it?
- Percent w/v means grams of solute per 100 mL of solution. So 1 percent w/v equals 10 g/L. Divide by the molar mass to get molarity.
- Why do I need the molecular weight to convert solubility units?
- Mass units describe how much a substance weighs, while molar units describe how many molecules are present. These are linked only through the molar mass, so converting between the two families always requires the molecular weight.