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Chemistry · Ch 9 — Solutions

Colligative Properties

9.9

Colligative Properties

Pure water is tasteless; add sugar and it becomes sweet, add salt and it becomes salty. This shows that a solution's properties generally do depend on the chemical nature of the dissolved solute particles.

However, for an ideal dilute solution, four particular properties behave completely differently: they do not depend on what the solute chemically is -- only on how many solute particles (molecules or ions) are present in the solution. These four properties are:

  1. Relative lowering of vapour pressure (section 9.9.1)
  2. Elevation of boiling point (section 9.9.2)
  3. Depression of freezing point (section 9.9.3)
  4. Osmotic pressure (section 9.9.4) …