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Gas Mixtures and Gas Stoichiometry: Flashcards

Revise Dalton's law, mole fractions, collecting gases over water, molar volume and gas stoichiometry.

10 cardsIntermediate

10 cards

  1. Question
    State Dalton's law of partial pressures.
    Answer

    The total pressure of a gas mixture is the sum of the partial pressures: P(total) = P(A) + P(B) + ...

  2. Question
    How is a partial pressure related to the mole fraction?
    Answer

    P(A) = x(A) × P(total), where x(A) = n(A) ÷ n(total).

  3. Question
    Air is 21 % O₂. What is the partial pressure of O₂ at 1.00 atm?
    Answer

    About 0.21 atm.

  4. Question
    How do you find the pressure of a dry gas collected over water?
    Answer

    P(gas) = P(total) − vapour pressure of water at that temperature.

  5. Question
    What is the molar volume of a gas at 0 °C and 1 atm? At 25 °C and 1 atm?
    Answer

    22.4 L/mol and 24.5 L/mol.

  6. Question
    State Avogadro's law.
    Answer

    Equal volumes of gases at the same temperature and pressure contain equal numbers of moles.

  7. Question
    Outline the steps of a gas stoichiometry calculation.
    Answer

    Convert to moles (n = PV/RT or from mass) → mole ratio from the equation → convert to the answer (V = nRT/P or mass).

  8. Question
    For gases at the same T and P, what volume of O₂ reacts with 2.00 L of C₃H₈? (C₃H₈ + 5O₂ → 3CO₂ + 4H₂O)
    Answer

    10.0 L: volume ratios equal mole ratios.

  9. Question
    What do the mole fractions in a mixture add up to?
    Answer

    1

  10. Question
    Which value of R goes with pressures in atm and volumes in L?
    Answer

    0.08206 L·atm/(mol·K)