a. <span>
<span>The balanced equation for the reaction between sulfuric acid and aluminium hydroxide is,
<span>
3H</span>₂SO₄<span> </span>+ 2Al(OH)₃ </span><span>→ Al₂(SO₄)₃<span> + 6H</span>₂O</span><span>
</span></span>
mass of H₂SO₄<span> = <span> 30.0 g
</span></span><span>
<span>Molar mass of H</span>₂SO₄</span><span> = 98 g/mol</span><span>
moles of H₂SO₄</span><span> = 30.0 g /98g /mol = 0.306 mol</span><span>
mass of Al(OH)₃</span><span> = 25.0 g </span><span>
Molar mass of Al(OH)₃</span> = 78 g/mol<span>
moles of Al(OH)₃<span> </span>= 25.0 g/ 78 g/mol = 0.321 mol</span><span>
Stoichiometric ratio between H₂SO₄<span> and </span>Al(OH)₃ is 3 : 2</span><span>
Hence reacted moles of H₂SO₄ = 0.306 mol</span><span>
reacted
moles of Al(OH)₃ =
0.306 mol x (2 / 3) = 0.204 mol</span><span>
Hence the limiting reactant is H₂SO₄</span>
<span>
b.<span>
</span>According to the above calculation, the excess
reactant is Al(OH)₃. </span><span>
The reacted moles of Al(OH)₃<span> = </span>0.306 mol x (2 / 3) = 0.204 mol</span><span>
The added moles of Al(OH)₃ = 0.321 mol</span><span>
Hence the remaining Al(OH)₃ moles = added moles - reacted moles</span><span>
=
0.321 mol - 0.204 mol
=
0.117 mol
Molar mass of Al(OH)₃</span> = 78 g/mol<span>
<span>Remaining mass of Al(OH)</span>₃ =
number of moles x molar mass</span><span>
= 0.117 mol x 78 g/mol
=
9.126 g
</span>
<span><span>
</span>
c.
</span>
The products formed from the reaction between
aluminium hydroxide and sulfuric acid are Al₂(SO₄)₃<span> and </span>H₂O<span>
The limiting reactant is H₂SO₄</span> <span>
The stoichiometric ratio between H₂SO₄
and Al₂(SO₄)₃</span> is 3 : 1<span>
Reacted moles of H₂SO₄ =
0.306 mol</span><span>
Hence the moles of Al₂(SO₄)₃ formed = 0.306 mol / 3</span><span>
= 0.102 mol
Molar mass of Al₂(SO₄)₃</span> = 342 g/mol<span>
Mass of Al₂(SO₄)₃</span> formed = 0.102 mol x 342 g/mol<span>
<span>
= </span>34.884 g
The stoichiometric ratio between H₂SO₄
and H₂O is 3 : 6</span><span>
Reacted moles of H₂SO₄ =
0.306 mol</span><span>
Hence the moles of H₂O formed = 0.306 mol x (6 / 3)</span><span>
= 0.612 mol
Molar mass of H₂O = 18 g/mol</span><span>
Mass of H₂O formed = 0.612 mol x 18 g/mol</span><span>
<span>
= </span><span>11.016 g</span></span>
