Question

Sulfuric acid dissolves aluminum metal according to the following reaction: 2Al(s)+3H2SO4(aq)→Al2(SO4)3(aq)+3H2(g) Suppose you wanted to dissolve an aluminum block with a mass of 14.5 g . Part A What minimum mass of H2SO4 would you need? I got 79.1 g, which is correct. Part B What mass of H2 gas would be produced by the complete reaction of the aluminum block? Express your answer in grams.

Answer 1

The reaction is,

2Al(s)+3H2SO4(aq)→Al2(SO4)3(aq)+3H2(g)

According to the stoichiometry of the reaction 2 moles of Al reacts to produce 3 moles of H2

Given,

Mass of Al = 14.5 gm

We know that,

Molar Mass of Al = 27 g / mol

=> Moles of Al = 14.5 / 27 = 0.537 moles

Since,

2 moles of Al reacts to produce 3 moles of H2

0.537 moles of Al will produce 1.5 x 0.537 = 0.81 moles of H2

=> Mass of H2 = 0.81 x 2 = 1.62 g of H2 would be produced by the complete reaction of the aluminium block