Concentrations based on weight :

Weight/weight percent (%w/w) : The weight of the solute in grams per 100 grams of solution

Molality (m) : the number of moles of solute per 1000 grams of solvent

Mole fraction (X_i) : Mole fraction of a compound in a solution is the fraction of the total number of moles represented by the compound in question. If a solution contains n₁ moles of compound 1, n₂ moles of compound 2, n₃ moles of compound 3, and n₄ moles of compound 4; the mole fraction of compound 3 is given by:

(2.9)

We shall be discussing about the buffers and preparation of buffers in the next lecture.