Gb asked in Science & MathematicsChemistry · 11 months ago

Chemistry Help Urgent?

In aqueous solution, hydrochloric acid, HCl, and solid aluminum metal, Al react to produce gaseous hydrogen, H2 and aluminum chloride,

AlCl3. A 5.00 g impure sample of Al is dissolved completely in water; then treated with 2.00 mol L−1 HCl to evolve 6409 mL of H2 at 25.0 °C and 100 kPa.

The HCl solution is slowly added until the evolution of H2 is no longer observed.

a)Write down the balanced chemical equation for the reaction described above. Please include all phases (i.e. aq, s, l, g, etc...).

b) b)What percent (by mass) of the impure sample is Al? Assume that the impure components of the sample do not react with HCl.

1 Answer

  • 11 months ago
    Favorite Answer

    Ignoring the fact that Al does not dissolve in water:


    2 Al(aq) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g)


    n = PV / RT = (100 kPa) x (6.409 L) / ((8.3144626 L kPa/K mol) x (25.0 + 273.15) K) =

    0.258536 mol H2

    (0.258536 mol H2) x (2 mol Al / 3 mol H2) x (26.98154 g Al/mol) / (5.00 g total) = 0.93009 =

    93.0% Al by mass

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