Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel rocket motors. The reaction is given below.

Fe2O3(s) + 2 Al(s) 2 Fe(l) + Al2O3(s)

What masses of iron(III) oxide and aluminum must be used to produce 30.0 g iron? What is the maximum mass of aluminum oxide that could be produced?

You must learn that equations have an arrow for a reason; i.e., to separate reactants from products. How do I know which is which?

To determine the masses of iron(III) oxide (Fe2O3) and aluminum (Al) needed, we need to use stoichiometry and molar masses.

1. Calculate the molar mass of Fe2O3:
Molar mass of Fe = 55.85 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of Fe2O3 = (2 * Molar mass of Fe) + (3 * Molar mass of O)
= (2 * 55.85 g/mol) + (3 * 16.00 g/mol)
= 159.70 g/mol

2. Convert the mass of iron (30.0 g) to moles:
Moles of Fe = Mass of Fe / Molar mass of Fe
= 30.0 g / 55.85 g/mol
= 0.537 moles

3. Use the balanced equation to relate the moles of Fe2O3 to moles of Fe:
From the balanced equation: 1 mol Fe2O3 : 2 mol Fe
So, Moles of Fe2O3 = (2 * Moles of Fe)
= (2 * 0.537 mol)
= 1.07 moles

4. Calculate the mass of Fe2O3 needed:
Mass of Fe2O3 = Moles of Fe2O3 * Molar mass of Fe2O3
= 1.07 moles * 159.70 g/mol
= 170.62 g

Therefore, to produce 30.0 g of iron, we need to use approximately 170.62 g of iron(III) oxide.

To determine the maximum mass of aluminum oxide (Al2O3) that could be produced, we can apply the same approach.

5. Calculate the molar mass of Al2O3:
Molar mass of Al = 26.98 g/mol
Molar mass of Al2O3 = (2 * Molar mass of Al) + (3 * Molar mass of O)
= (2 * 26.98 g/mol) + (3 * 16.00 g/mol)
= 101.96 g/mol

6. Use the balanced equation to calculate the moles of Al2O3 produced:
From the balanced equation: 1 mol Fe2O3 : 1 mol Al2O3
So, Moles of Al2O3 = Moles of Fe2O3
= 1.07 mol

7. Calculate the mass of Al2O3 produced:
Mass of Al2O3 = Moles of Al2O3 * Molar mass of Al2O3
= 1.07 moles * 101.96 g/mol
= 109.10 g

Therefore, the maximum mass of aluminum oxide that could be produced in this reaction is approximately 109.10 g.