Question

3. In a thermite reaction, aluminum powder undergoes a redox reaction with rust. If 55.0 g of

aluminum reacts completely, what mass of iron is formed? Start by balancing the
equation. Show your work. (3 pts) Al + Fe₂O3 Fe + Al₂O3

Answer 1

Balanced equation: 2Al + Fe₂O₃ → 2Fe + Al₂O₃

Molar mass of aluminum (Al) = 26.98 g/mol

Molar mass of iron (Fe) = 55.85 g/mol

Molar mass of rust (Fe₂O₃) = 159.69 g/mol

Number of moles of aluminum: 55.0 g / 26.98 g/mol = 2.04 mol

Using mole ratio, we can determine that 2 moles of aluminum react with 1 mole of rust to produce 2 moles of iron.

Therefore, number of moles of iron formed = 2.04 mol / 2 = 1.02 mol

Mass of iron formed: 1.02 mol × 55.85 g/mol = 57.0 g

Therefore, 57.0 g of iron is formed.