Answer:
58.78 g Al₂O₃
Explanation:
To find the mass of aluminum oxide (Al₂O₃) produced, you need to (1) convert grams Fe to moles Fe (via the molar mass), then (2) convert moles Fe to moles Al₂O₃ (via the mole-to-mole ratio from equation coefficients), and then (3) convert moles Al₂O₃ to grams Al₂O₃ (via the molar mass). It is important that the conversions/ratios are arranged in a way that allows for the cancellation of units. The final answer should have 4 sig figs like the given value (64.39 g).
Molar Mass (Fe): 55.845 g/mol
Molar Mass (Al₂O₃): 2(26.982 g/mol) + 3(15.998 g/mol)
Molar Mass (Al₂O₃): 101.958 g/mol
Fe₂O₃(s) + 2 Al(s) -----> 2 Fe(l) + 1 Al₂O₃(s)
^ ^
64.39 g Fe 1 mole 1 mole Al₂O₃ 101.958 g
------------------- x ------------------ x ---------------------- x ------------------ =
55.845 g 2 moles Fe 1 mole
= 58.78 g Al₂O₃
