Question Detail

MgCl₂ dissociates into 3 ions per formula unit. Number of formula units = (5.0 × 10²³ ions) / 3 = 1.667 × 10²³ formula units. Moles = 1.667×10²³ / 6.022×10²³ = 0.2768 mol. Molar mass MgCl₂ = 24 + 71 = 95 g/mol. Mass = 0.2768 × 95 = 26.3 g. None match. If it's 5.0 × 10²³ Cl⁻ ions, then moles Cl⁻ = 0.8305, moles MgCl₂ = 0.4153, mass = 39.45 g. If it's 5.0 × 10²³ Mg²⁺ ions, moles = 0.8305, mass = 78.9 g. The intended is likely 78.9 g for Mg²⁺ ions.