Final answer:
The calculated molar mass of iron oxide (Fe2O3) is 159.687 g/mol, and the molar mass of aluminum oxide (Al2O3) is 101.961 g/mol, both to four significant figures. These values are obtained using the atomic masses from the periodic table and are fundamental for stoichiometry calculations involving mass relationships in chemical equations.
Step-by-step explanation:
To calculate the molar masses of iron oxide (Fe2O3) and aluminum oxide (Al2O3), we first need to determine the atomic masses of the elements iron (Fe), oxygen (O), and aluminum (Al) from the periodic table. The atomic mass of Fe is approximately 55.845 g/mol, O is about 15.999 g/mol, and Al is approximately 26.982 g/mol. To find the molar mass of Fe2O3, multiply the atomic mass of Fe by 2 and add it to the atomic mass of O multiplied by 3, which gives us:
(2 × 55.845 g/mol) + (3 × 15.999 g/mol) = 111.69 g/mol + 47.997 g/mol = 159.687 g/mol
Therefore, the molar mass of iron oxide (Fe2O3) is 159.687 g/mol to four significant figures. Similarly, the molar mass of aluminum oxide (Al2O3) is calculated by:
(2 × 26.982 g/mol) + (3 × 15.999 g/mol) = 53.964 g/mol + 47.997 g/mol = 101.961 g/mol
Hence, the molar mass of aluminum oxide (Al2O3) is 101.961 g/mol to four significant figures. Using molar masses and stoichiometry, we can determine the mass-mass calculations and mass relationships in chemical reactions.