A commercial sample of pyrite (FeS2) is oxidized by bromine and nitric acid. The sulphate obtained is precipitated and heavy in the form of BaSO4. If 0, 331g of pyrite originated 0.813 g of BaSO4, what is the% of sulphur in the studied pyrite? What is the% of FeS2??
g FeS2 = 0..813 g BaSO4 x (molar mass FeS2/2*molar mass BaSO4) = ?. The is the actual yield (AY) of FeS2. Mass sample is 0.331 g.
%yield = (AY/mass sample)*100 = ?
To find the percentage of sulfur in the studied pyrite (FeS2), we need to calculate the molar quantity of sulfur in BaSO4 and then convert it to a percentage.
Step 1: Calculate the molar mass of BaSO4.
BaSO4 consists of one barium ion (Ba2+) and one sulfate ion (SO42-).
The molar mass of Ba2+ = atomic mass of Ba = 137.33 g/mol
The molar mass of SO42- = atomic mass of S + (4 * atomic mass of O) = 32.06 + (4 * 16.00) = 96.06 g/mol
The molar mass of BaSO4 = (Atomic mass of Ba) + (Atomic mass of S) + (4 * Atomic mass of O)
= 137.33 + 32.06 + (4 * 16.00)
= 233.38 g/mol
Step 2: Calculate the molar quantity of BaSO4.
Given that 0.813 g of BaSO4 was obtained from 0.331 g of pyrite (FeS2), we can find the molar quantity of BaSO4 using its molar mass.
Molar quantity of BaSO4 = Mass of BaSO4 / Molar mass of BaSO4
= 0.813 g / 233.38 g/mol
Step 3: Calculate the molar quantity of sulfur (S).
In BaSO4, there is one sulfur atom for every one BaSO4 unit. Thus, the molar quantity of sulfur is the same as the molar quantity of BaSO4.
Step 4: Calculate the molar mass of S.
The atomic mass of S is 32.06 g/mol.
Step 5: Calculate the percentage of sulfur in the studied pyrite.
Percentage of sulfur = (Molar quantity of S * Molar mass of S) / Mass of pyrite * 100
= (Molar quantity of BaSO4 * Molar mass of S) / Mass of pyrite * 100
= [(0.813 g / 233.38 g/mol) * 32.06 g/mol] / 0.331 g * 100
Now, simply plug in these values and solve the equation to find the percentage of sulfur in the studied pyrite.
To find the percentage of FeS2 in the studied pyrite, subtract the percentage of sulfur from 100%.