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Electrolytes and Dissolving: Flashcards

Revise solutes and solvents, hydration, strong, weak and non-electrolytes, ion concentrations and energy changes on dissolving.

10 cardsBeginner

10 cards

  1. Question
    What are the solute and the solvent in a solution?
    Answer

    Solute: the substance dissolved. Solvent: the substance it dissolves in (usually present in larger amount, often water).

  2. Question
    What is an electrolyte?
    Answer

    A substance that forms ions in water, so its solution conducts electricity.

  3. Question
    Give examples of strong, weak and non-electrolytes.
    Answer

    Strong: NaCl, HCl, NaOH. Weak: ethanoic acid, ammonia. Non-electrolyte: sugar, ethanol.

  4. Question
    What does "hydrated" mean for an ion?
    Answer

    The ion is surrounded by water molecules, with their oppositely charged ends facing it.

  5. Question
    Which end of a water molecule faces a Na⁺ ion?
    Answer

    The oxygen (δ−) end.

  6. Question
    Write the dissociation equation for CaCl₂.
    Answer

    CaClX2(s)→CaX2+(aq)+2 ClX−(aq)\ce{CaCl2(s) -> Ca^2+(aq) + 2Cl-(aq)}

  7. Question
    What is [Cl⁻] in 0.150 mol/L CaCl₂?
    Answer

    2 × 0.150 mol/L = 0.300 mol/L

  8. Question
    Why does sugar solution not conduct electricity?
    Answer

    Sugar dissolves as whole molecules and forms no ions.

  9. Question
    What two energy steps occur when an ionic solid dissolves?
    Answer

    Breaking the lattice (endothermic) and hydrating the ions (exothermic).

  10. Question
    Why does dissolving NH₄NO₃ make water colder?
    Answer

    Hydration releases less energy than breaking the lattice needs, so heat is taken from the water (ΔH positive).