Here are some ways to express concentration:
* Molarity (M): Moles of solute per liter of solution.
* Molality (m): Moles of solute per kilogram of solvent.
* Mass percent (%): Mass of solute divided by the mass of solution, multiplied by 100%.
* Parts per million (ppm): Mass of solute divided by the mass of solution, multiplied by 1,000,000.
* Parts per billion (ppb): Mass of solute divided by the mass of solution, multiplied by 1,000,000,000.
The specific unit of concentration used depends on the context and the desired level of precision.
