1) Concentration expressed as number of moles of solute per kilogram of solvent.
2) is the number of moles of solute dissolved in one kilogram of solvent. Note: be careful not to confuse molality and molarity. Molality is represented by a small "m," whereas molarity is represented by an upper case "M."
3) The number of moles of solute in 1 kilogram of solvent.