<h3>
Answer:</h3>
Al₂(SO₄)₃
<h3>
Explanation:</h3>
We are given percentage composition of elements in a compound;
- Aluminium is 15.77%
- Sulfur is 28.11 %
- Oxygen is 56.12%
We are required to calculate the empirical formula of the compound.
- Assuming the mass of the compound is 100 g then the masses of the elements is;
Aluminium = 15.77 g
Sulfur = 28.11
Oxygen = 56.12
We can determine the number of moles of each;
Moles of Aluminium = 15.77 g ÷ 26.98 g/mol
= 0.585 moles
Moles of sulfur = 28.11 g ÷ 32.07 g/mol
= 0.877 moles
Moles of Oxygen = 56.12 g ÷ 16.0 g/mol
= 3.5075 moles
- But, the empirical formula is the simplest whole number ratio of elements in a compound.
- Therefore; we need to get the ratio of moles of the above elements;
Aluminium : Sulfur : Oxygen
0.585 mol : 0.877 mol : 3.5075 mol
0.585/0.585 : 0.877/0.585 : 3.5075/0.585
1 : 1.5 : 6
But, we need whole number ratios, therefore;
= (1 : 1.5 : 6 ) × 2
= 2 : 3 : 12
Therefore; the formula of the compound is Al₂S₃O₁₂
The compound is written as Al₂(SO₄)₃
Thus, the empirical formula of the compound is Al₂(SO₄)₃
