Concentration is a measure of the amount of solute present in a given amount of solvent or solution.
There are several methods to express concentration, each with its own formula.
1) Mass percentage (w/w):
Mass percentage is the mass of solute present in a given mass of solution, expressed as a percentage.
Formula: Mass % = (mass of solute / mass of solution) × 100%
2) Volume percentage (v/v):
Volume percentage is the volume of solute present in a given volume of solution, expressed as a percentage.
Formula: Volume % = (volume of solute / volume of solution) × 100%
3) Mass/volume percentage (w/v):
Mass/volume percentage is the mass of solute present in each volume of solution, expressed as a percentage.
Formula: Mass/volume % = (mass of solute / volume of solution) × 100%
4) Molarity (M):
Molarity is the number of moles of solute present in one liter of solution.
Formula: M = moles of solute / liters of solution.
5) Molality (m):
Molality is the number of moles of solute present in one kilogram of solvent.
Formula: m = moles of solute / kilograms of solvent
6) Mole fraction (χ):
Mole fraction is the ratio of the number of moles of one component to the total number of moles in the mixture.
Formula: χ_A = moles of A / (moles of A + moles of B)
7) Normality (N):
Normality is the number of gram-equivalents of solute present in one liter of solution.
Formula: N = gram-equivalents of solute / liters of solution