Question below:

Question

Consider the following reaction:

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

If 3.0 mol of Al were used in the reaction, then _______mol of H2SO4 is needed to complete the 

reaction, and would produce_______g of hydrogen gas as well as ______g of Al2(SO4)3 would be 

produced.

Answer 1

2Al(s) + 3H₂SO₄(aq) ==> 3H₂(g) + Al₂(SO₄)₃(aq) ... balanced equation

From the balanced equation, we can see the mole ratios among the different species. For example, the mole ratio between Al(s) and H₂SO₄(aq) is 2 : 3. Using this ratio and dimensional analysis, we can find moles of H₂SO₄ used when 3 mols Al are used.

3.0 mols Al x 3 mols H₂SO₄ / 2 mol Al = 4.5 mols H₂SO₄ needed

Following the same procedure, we can now find grams of H₂ and Al₂(SO₄)₃

For H2: 3 mols Al x 3 mols H2 / 2 mols Al x 2 g H2 / mol H2 = 9.0 g H₂

For Al₂(SO₄)₃: 3 mols Al x 1 mol Al₂(SO₄)₃ / 2 mols Al x 342 g Al₂(SO₄)₃ / mol = 513 g Al₂(SO₄)₃

This would be rounded to 510 g (2 sig. figs.)