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Solubility and Colligative Properties: Flashcards

Revise solubility, Henry's law, molality, the van 't Hoff factor, freezing-point depression, boiling-point elevation and osmotic pressure.

10 cardsIntermediate

10 cards

  1. Question
    How does temperature affect the solubility of solids and gases?
    Answer

    Most solids dissolve more when hot; gases dissolve less when hot.

  2. Question
    State Henry's law.
    Answer

    The solubility of a gas is proportional to its pressure above the liquid: c = k(H) × P.

  3. Question
    What is a colligative property?
    Answer

    A property that depends only on the number of dissolved particles, not their identity.

  4. Question
    Define molality.
    Answer

    Moles of solute per kilogram of solvent (mol/kg).

  5. Question
    van 't Hoff factor for glucose, NaCl and CaCl₂?
    Answer

    1, 2 and 3 (ideal values).

  6. Question
    Freezing-point depression equation?
    Answer

    ΔTf = i Kf m; for water Kf = 1.86 °C kg/mol. Subtract from the normal freezing point.

  7. Question
    Boiling-point elevation equation?
    Answer

    ΔTb = i Kb m; for water Kb = 0.512 °C kg/mol. Add to the normal boiling point.

  8. Question
    Osmotic pressure equation?
    Answer

    Π = iMRT, with M in mol/L, R = 0.08206 L atm mol⁻¹ K⁻¹, T in K.

  9. Question
    What is osmosis?
    Answer

    Flow of solvent through a semipermeable membrane from a dilute solution into a more concentrated one.

  10. Question
    Why does salt melt ice on roads?
    Answer

    Dissolved ions lower the freezing point of water (freezing-point depression), so the ice melts below 0 °C.