Question

Thermite is a mixture of iron(iii) oxide and aluminum powders that undergoes a reaction to form solid aluminum oxide and molten iron.

Fe₂O₃(s) + 2Al(s) → Al₂O₃(s) + 2Fe(l)
using the balanced reaction above, how many atoms of aluminum react for every 1.00 g of aluminum oxide that forms?

Answer 1

To determine how many atoms of aluminum react for every 1.00 g of aluminum oxide that forms in the thermite reaction, calculate the moles of aluminum oxide from its mass, use stoichiometry to find the moles of aluminum, and then multiply by Avogadro's number to get atoms.

Step-by-step explanation:

The question at hand involves a stoichiometric calculation based on a balanced chemical equation. In the thermite reaction, aluminum (Al) reacts with iron(III) oxide (Fe2O3) to produce aluminum oxide (Al2O3) and molten iron (Fe). The balanced equation for this exothermic reaction is 2 Al(s) + Fe2O3(s) → Al2O3(s) + 2 Fe(l), indicating that 2 moles of aluminum react to form 1 mole of aluminum oxide.

To determine the number of aluminum atoms reacting per 1.00 g of aluminum oxide formed, we begin by calculating the molar mass of Al2O3, which is approximately 101.96 g/mol. Using this, we find that 1.00 g of Al2O3 corresponds to 1.00 g / 101.96 g/mol = 9.81 x 10-3 moles of Al2O3.

Based on the balanced equation, 2 moles of Al yield 1 mole of Al2O3. Therefore, 9.81 x 10-3 moles of Al2O3 is produced from 2 x 9.81 x 10-3 moles of Al. We then convert the moles of aluminum to atoms by multiplying by Avogadro's number (6.022 x 1023 atoms/mole), resulting in 1.179 x 1022 aluminum atoms reacting per 1.00 g of aluminum oxide formed.