Calculate the molar mass of CuSO4·5H2O

To find the molar mass of CuSO₄·5H₂O, we need to sum the molar masses of its components: copper (Cu), sulfur (S), oxygen (O), and the water molecules (H₂O).

• Molar mass of Cu = 63.55 g/mol
• Molar mass of S = 32.07 g/mol
• Molar mass of O = 16.00 g/mol (and there are 4 oxygen atoms in CuSO₄ and 5 in 5H₂O, totaling 9)
• Molar mass of H₂O = (2 x 1.01) + 16.00 = 18.02 g/mol (for 5 H₂O, multiply by 5)

Now calculate:

• Total mass of CuSO₄ = 63.55 + 32.07 + (4 x 16.00) = 63.55 + 32.07 + 64.00 = 159.62 g/mol
• Total mass of 5H₂O = 5 x 18.02 = 90.10 g/mol

Finally, add the two amounts together:

159.62 g/mol (for CuSO₄) + 90.10 g/mol (for 5H₂O) = 249.72 g/mol

Thus, the molar mass of CuSO₄·5H₂O is approximately 249.70 g/mol.

Answer: b) 249.70 g/mol