Question

A 3.00g sample of an alloy (containing only Pb and Sn) was dissolved in nitric acid (HNO₃). Sulfuric acid was added to this solution, which precipitated 2.58 g of PbSO₄. Assuming that all of the lead was precipitated, what is the percentage of Sn in the sample? (molar mass of PbSO₄ = 303.3 g/mol) a) 46.0% sn b) 0.781% sn c) 79.0% sn d) 54.0% sn e) 1.62% sn

Answer 1

To find the percentage of Sn in the alloy, calculate the moles of PbSO4 precipitated, determine the corresponding mass of Pb using its molar mass, subtract this from the total mass of the sample to get the mass of Sn, and calculate the percentage.

The correct option is not given.

Step-by-step explanation:

The student is asking for the percentage of Sn in an alloy after a gravimetric analysis involving precipitation of PbSO4. To solve this, we'll use the given molar mass of PbSO4 and the molar mass of Pb to find the mass of Pb in the original sample. Then we'll subtract that mass from the total mass of the sample to find the mass of Sn and calculate the percentage:

1. Calculate the moles of PbSO4:
   Moles of PbSO4 = mass of PbSO4 / molar mass of PbSO4 = 2.58 g / 303.3 g/mol
2. Since the molar mass of Pb is 207 g/mol (from provided material), and each mole of PbSO4 contains one mole of Pb, calculate the mass of Pb:
   Mass of Pb = moles of PbSO4 * molar mass of Pb
3. Calculate the mass of Sn in the sample by subtracting the mass of Pb from the total mass of the sample:
4. Finally, calculate the percentage of Sn by dividing the mass of Sn by the total mass of the sample and then multiplying by 100.

After carrying out the calculations, we find the percentage of Sn in the sample.

The correct option is not given.