Copper sulphate hydrated questions related to Number of moles?

17.
a.
Molar mass of BaSO₄ = (137.3 + 32.1 + 16.0×4) g/mol = 233.4 g/mol
Moles of BaSO₄ formed = (3.739 × 10⁻² g) / (233.4 g/mol) = 1.602 × 10⁻⁴ mol

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b.
CuSO₄(aq) + BaCl₂(aq) → BaSO₄(s) + CuCl₂(aq)

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c.
According to the equation in part b, mole ratio CuSO₄ : BaSO₄ = 1 : 1
Moles of CuSO₄ reacted with BaCl₂ = Moles of BaSO₄ formed = 1.602 × 10⁻⁴ mol

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d.
Moles of CuSO₄ reacted with BaCl₂ = (10/100) × (Moles of CuSO₄•xH₂O used)
Moles of CuSO₄•xH₂O used = (1.602 × 10⁻⁴ mol) × (100/10) = 1.602 × 10⁻³ mol

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e.
Molar mass of CuSO₄•xH₂O in g/mol:
63.5 + 32.1 + 16.0×4 + x(1.0×2 + 16.0) = 0.4000/(1.602 × 10⁻³)
159.6 + 18.0x = 249.7
18.0x = 90.1
x = 5