Answer:
0.375 moles Al
Explanation:
To find the moles Al, you need to (1) convert grams AlCl₃ to moles AlCl₃ (via molar mass) and then (2) convert moles AlCl₃ to moles Al (via mole-to-mole ratio from equation coefficients). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value (50.0 g).
Molar Mass (AlCl₃): 26.982 g/mol + 3(35.453 g/mol)
Molar Mass (AlCl₃): 133.341 g/mol
2 Al(s) + 3 CuCl₂(aq) -----> 3 Cu(s) + 2 AlCl₃(aq)
50.0 g AlCl₃ 1 mole 2 moles Al
-------------------- x ------------------ x ----------------------- = 0.375 moles Al
133.341 g 2 moles AlCl₃
