Question

(b) Use the data above to calculate the number of moles of

Ag
2
SO
4
(
s
)
(molar mass
311.8
g/mol
) that precipitated.

Answer 1

To calculate the number of moles of
`Ag_2SO_4` that precipitated, divide the mass of the precipitate by its molar mass. In this example, using 2.00 g of
`Ag_2SO_4` and a molar mass of 311.8 g/mol, the result is approximately 0.00642 moles of
`Ag_2SO_4`.

The process begins with the given mass of precipitate, which is 2.00 grams of
`Ag_2SO_4`. To determine the number of moles, we use the formula n = m / M, where n is the number of moles, m is the mass of the substance, and M is the molar mass of the substance.

The molar mass of
`Ag_2SO_4` can be calculated by summing the atomic masses of its constituent atoms: 2 × Ag (silver) + 1 × S (sulfur) + 4 × O (oxygen). Using atomic masses from the periodic table, we find M = 2 × 107.87 g/mol + 32.06 g/mol + 4 × 16.00 g/mol ≈ 311.8 g/mol.

Substituting the values into the formula, we get n = 2.00 g / 311.8 g/mol ≈ 0.00642 mol. Therefore, approximately 0.00642 moles of
`Ag_2SO_4`precipitated during the reaction.

This calculation is fundamental in stoichiometry, allowing chemists to relate the mass of reactants and products to the number of moles involved in a chemical reaction. It provides a quantitative understanding of the reaction and facilitates accurate analysis and synthesis in chemical processes.