Question

An ore sample is known to contain copper sulfate pentahydrate, CuSO4•5H2O. If a 9.661 g sample of the ore loses 1.0447 g of water when heated strongly, what is the maximum mass, in grams, of CuSO4•5H2O that could have been in the sample? (MW of CuSO4•5H2O = 249.55 g/mol)

Answer 1

To determine the maximum mass of CuSO4·5H2O in a heated ore sample, we calculate the moles of water evaporated, use the stoichiometry of the compound to find the corresponding moles of CuSO4·5H2O, and multiply by its molar mass to find the mass.

Step-by-step explanation:

The student is asking about the mass of CuSO4·5H2O in a given ore sample based on the mass of water lost when heated. To find this, we use the molar mass of CuSO4·5H2O. The molar mass of CuSO4·5H2O is 249.55 g/mol. We calculate the moles of water lost by the sample by using the molar mass of water (18.015 g/mol) and then use the stoichiometry of the compound to find the number of moles of CuSO4·5H2O that corresponds to the lost water. Then, we multiply the moles of CuSO4·5H2O by its molar mass to get the mass.

First, calculate the moles of water lost: (1.0447 g) / (18.015 g/mol) = 0.058 moles of water. Because the ratio of water to CuSO4·5H2O in the compound is 5:1, the moles of CuSO4·5H2O will be (0.058 moles) / 5 = 0.0116 moles. Finally, multiply this by the molar mass of CuSO4·5H2O to get the maximum mass of the compound in the sample: (0.0116 moles) x (249.55 g/mol) = 2.89458 g of CuSO4·5H2O.