A compound is found to contain 63.52 % iron and 36.48 % sulfur. Find its empirical formula.
FeS
FeS2
Fe2S
Fe2s3
look at 100 g of the compound
63.52 g Fe and 36.48 g S
the formula is by moles
... so divide the weights by the molar masses
... the ratio of the quotients is the ratio of the atoms
... 1:1 , 1:2 etc.
To find the empirical formula of a compound, you need to determine the simplest ratio between the atoms in the compound. In this case, you'll be working with the percentages of iron and sulfur.
1. Start by assuming you have 100 grams of the compound so that the percentages can be directly converted to grams.
Iron: 63.52% of 100 g = 63.52 g
Sulfur: 36.48% of 100 g = 36.48 g
2. Next, convert the masses of iron and sulfur to moles by dividing them by their respective atomic masses.
Iron (Fe): atomic mass = 55.85 g/mol
Moles of Fe = 63.52 g / 55.85 g/mol ≈ 1.14 mol
Sulfur (S): atomic mass = 32.06 g/mol
Moles of S = 36.48 g / 32.06 g/mol ≈ 1.14 mol
3. Divide the moles of each element by the smallest number of moles to obtain the simplest whole number ratio of atoms.
Moles ratio of Fe : S = 1.14 mol : 1.14 mol
The ratio simplifies to 1:1.
Therefore, the empirical formula of the compound is FeS.
To find the empirical formula of the compound, we need to determine the ratio of elements in the compound based on their masses or percentages.
Let's assume we have 100 grams of the compound.
1. Calculate the mass of iron (Fe) in the compound:
Mass of Fe = 63.52% × 100 g = 63.52 g
2. Calculate the mass of sulfur (S) in the compound:
Mass of S = 36.48% × 100 g = 36.48 g
3. Convert the mass of each element to moles:
Moles of Fe = 63.52 g / atomic mass of Fe
Moles of S = 36.48 g / atomic mass of S
The atomic mass of Fe is approximately 55.845 g/mol.
The atomic mass of S is approximately 32.06 g/mol.
Moles of Fe = 63.52 g / 55.845 g/mol ≈ 1.138 mol
Moles of S = 36.48 g / 32.06 g/mol ≈ 1.137 mol
4. Divide the number of moles of each element by the smallest number of moles to get the simplest whole number ratio of atoms:
Moles ratio of Fe : S = 1.138 mol : 1.137 mol
(Divide by the smallest number of moles, which is approximately 1.137 mol)
Simplified ratio of Fe : S = 1 : 1
Therefore, the empirical formula of the compound is FeS.