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2018-08-24 7:20 am

Hydrochloric acid reacts with aluminum to produce hydrogen gas according to the following reaction.

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

If HCl is combined with 39.4 g of Al, what volume of hydrogen gas can be produced at STP?

16.3 L

98.1 L

2.19 L

49.0 L

回答 (1)

胡雪8°

2018-08-24 9:03 am

✔ 最佳答案

Molar mass of Al = 27.0 g/mol
No. of moles of Al reacted = (39.4 g) / (27.0 g/mol) = 1.459 mol

6HCl(aq) + 2Al(s) → 2AlCl₃(aq) + 3H₂(g)
Mole ratio Al : H₂ = 2 : 3
No. of moles of H₂ = (1.459 mol) × (3/2) = 2.189 mol

Molar volume of H₂ at STP = 22.4 L/mol
Volume of H₂ produced at STP = (2.189 mol) × (22.4 L/mol) = 49.0 L

The answer: 49.0 L

====
Alternative answer:

(39.4 g Al) × (1 mol Al / 27.0 g Al) × (3 mol H₂ / 2 mol Al) × (22.4 L H₂ at STP / 1 mol H₂)
= 49.0 L H₂ at STP

The answer: 49.0 L

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