<u>Answer:</u> The empirical and molecular formula of chrysotile is and
<u>Explanation:</u>
We are given:
Percentage of Mg = 28.03 %
Percentage of Si = 21.60 %
Percentage of H = 1.16 %
Percentage of O = 49.21 %
Let the mass of compound be 100 g. So, percentages given are taken as mass.
Mass of Mg = 28.03 g
Mass of Si = 21.60 g
Mass of H = 1.16 g
Mass of O = 49.21 g
To formulate the empirical formula, we need to follow some steps:
- <u>Step 1:</u> Converting the given masses into moles.
Moles of Magnesium =
Moles of Silicon =
Moles of Hydrogen =
Moles of Oxygen =
- <u>Step 2:</u> Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.752 moles.
For Magnesium =
For Silicon =
For Hydrogen =
For Oxygen =
To convert the mole ratios into whole numbers, we multiply individual mole ratios by 2
Mole ratio of Magnesium = (2 × 1.5) = 3
Mole ratio of Silicon = (2 × 1) = 2
Mole ratio of Hydrogen = (2 × 1.5) = 3
Mole ratio of Oxygen = (2 × 4) = 8
- <u>Step 3:</u> Taking the mole ratio as their subscripts.
The ratio of Mg : Si : H : O = 3 : 2 : 3 : 8
The empirical formula for the given compound is
For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.
The equation used to calculate the valency is :
We are given:
Mass of molecular formula = 520.8 g/mol
Mass of empirical formula = [(24 × 3) + (28 × 2) + (1 × 3) + (16 × 8)] = 259 g/mol
Putting values in above equation, we get:
Multiplying this valency by the subscript of every element of empirical formula, we get:
Hence, the empirical and molecular formula of chrysotile is and