Concentration of solution

The great majority of reactions studied and used in a chemistry laboratory are carried out with the reactants dissolved in a solution, so it is essential to be able to express precisely how much of a substance (the solute) is present in a given solution. This section covers four different, commonly used ways of expressing the concentration of a solution: mass percent or weight percent (w/w %), which compares the mass of solute to the total mass of solution; mole fraction, which compares the moles of one component to the total moles of all components; molarity (M), which expresses moles of solute per litre of solution; and molality (m), which expresses moles of solute per kilogram of solvent. Each of these is …