Commercial aluminum, weighing 15 g, containing 3.57% impurities, was treated with an excess

| February 6, 2021 | education

Commercial aluminum, weighing 15 g, containing 3.57% impurities, was treated with an excess of hydrochloric acid solution. Determine the volume of gas produced.

Let’s write the reaction equation:

2Al + 6HCl = 2AlCl3 + 3H2 ↑

Let’s find the mass fraction of aluminum in a sample of technical aluminum:

w (Al) = 100 – w (impurities) = 100 – 3.57 = 96.43 (%).

Let’s find the mass of aluminum:

m (Al) = m (Al) tech. * w (Al) / 100 = 15 * 96.43 / 100 = 14.4645 (g).

Let’s find the amount of aluminum substance:

v (Al) = m (Al) / M (Al) = 14.4645 / 27 = 0.5357 (2) (mol).

According to the reaction equation, 3 mol H2 is formed per 2 mol of Al, therefore:

v (H2) = v (Al) * 3/2 = 0.5357 (2) * 3/2 = 0.80358 (3) (mol).

Thus, the volume of released hydrogen, measured under normal conditions (n.o.):

V (H2) = v (H2) * Vm = 0.80358 (3) * 22.4 = 18.000 = 18 (l).

Answer: 18 liters.



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