Question

The weight of 1 x 10²² molecules of CuSO₄.5H₂O is 

(a) 41.59 g

(b) 415.9 g

(c) 4.159 g

(d) none of the three

Answer 1

Correct option is (c) 4.159 g

Molar mass of CuSO₄​⋅5H₂​O = 63.5 + 32 + 4 × 16 + 5 × 18 = 249.5 g/mol

Thus, 249.5 g of CuSO₄​⋅5H₂​O contains avogadro's number of molecules.

The weight of 1 × 10²² molecules of CuSO₄​⋅5H₂​O is \(\frac{249.5}{6.023\times 10^{23}} \times 10^{22}\) = 4.159 g