The number of moles of Cu reacted was — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The weight lost by the copper wire is purely due to the dissolution of copper solid into $\text{Cu}^{2+}$ ions. Mass lost = 6.35 mg = $6.35 \times 10^{-3}\text{ g}$. Moles of Cu reacted = $\frac{\text{Mass}}{\text{Molar Mass}} = \frac{6.35 \times 10^{-3}\text{ g}}{63.5\text{ g/mol}} = 1.0 \times 10^{-4}\text{ moles}$. Therefore, correct answer is A.