Aluminum metal reacts with iron(III) oxide to produce aluminum oxide and iron metal.
(a) How many moles of Fe2O3 are required to completely react with 55 g Al?
mol
(b) How many moles of Fe are produced by the reaction of 3.00 mol Fe2O3 and 97.7 g Al?
mol
(c) How many atoms of Al are required to produce 7.8 g Fe?
atoms
Here is an example I posted for stoichiometry problems.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To solve these problems, we need to calculate the number of moles using the molar mass and then use the balanced chemical equation to determine the mole ratios between reactants and products.
(a) To find the number of moles of Fe2O3 required to react with 55 g of Al, we need to determine the molar mass of Al and use it to convert grams to moles.
1. Look up the molar mass of Al from the periodic table: 26.98 g/mol
2. Use the molar mass to convert grams of Al to moles:
moles of Al = mass of Al / molar mass of Al
= 55 g / 26.98 g/mol
≈ 2.04 mol
3. Now, we need to determine the mole ratios between Al and Fe2O3 from the balanced chemical equation:
2 Al + Fe2O3 → Al2O3 + 2 Fe
According to the balanced equation, 2 moles of Al react with 1 mole of Fe2O3.
Therefore, the number of moles of Fe2O3 required is:
moles of Fe2O3 = 2.04 mol Al × (1 mol Fe2O3 / 2 mol Al)
= 1.02 mol
So, (a) The number of moles of Fe2O3 required to completely react with 55 g Al is approximately 1.02 mol.
(b) To find the number of moles of Fe produced when 3.00 mol of Fe2O3 reacts with 97.7 g of Al, we follow these steps:
1. Calculate the number of moles of Al using its molar mass:
moles of Al = mass of Al / molar mass of Al
= 97.7 g / 26.98 g/mol
≈ 3.62 mol
2. Now, use the mole ratios given by the balanced equation:
According to the balanced equation, 1 mole of Fe2O3 produces 2 moles of Fe.
Therefore, the number of moles of Fe produced is:
moles of Fe = 3.00 mol Fe2O3 × (2 mol Fe / 1 mol Fe2O3)
= 6.00 mol
So, (b) The number of moles of Fe produced by the reaction of 3.00 mol Fe2O3 and 97.7 g Al is 6.00 mol.
(c) To determine the number of atoms of Al required to produce 7.8 g Fe, we follow these steps:
1. Calculate the number of moles of Fe using its molar mass:
moles of Fe = mass of Fe / molar mass of Fe
= 7.8 g / 55.85 g/mol
≈ 0.14 mol
2. Now, we can use the mole ratios given by the balanced equation to find the number of moles of Al required:
According to the balanced equation, 2 moles of Al produce 1 mole of Fe.
Therefore, the number of moles of Al required is:
moles of Al = 0.14 mol Fe × (2 mol Al / 1 mol Fe)
= 0.28 mol
3. Finally, convert the number of moles of Al to the number of atoms of Al using Avogadro's number:
number of atoms of Al = moles of Al × Avogadro's number
= 0.28 mol × 6.022 × 10^23 atoms/mol
So, (c) The number of atoms of Al required to produce 7.8 g Fe is approximately 1.69 × 10^23 atoms.