Final answer:
There are 6 aluminum and 9 oxygen atoms in three formula units of Al2O3. When considering moles, this equates to 3.6132 × 10^24 aluminum atoms and 5.4198 × 10^24 oxygen atoms, totaling 9.033 × 10^24 atoms.
Step-by-step explanation:
To calculate how many atoms are in three formula units of Al2O3 (aluminum oxide), we must consider the chemical formula and Avogadro's number. Al2O3 contains 2 aluminum atoms and 3 oxygen atoms per formula unit.
Thus, three formula units of Al2O3 will have a total of 3 * 2 = 6 aluminum atoms and 3 * 3 = 9 oxygen atoms.
Using Avogadro's number to find the number of atoms in 3 moles of Al2O3, we multiply by the number of atoms per mole.
Each mole contains 6.022 × 1023 atoms, so 3 moles of Al2O3 would contain 3 × 6.022 × 1023, multiplied by the number of each type of atom in the formula.
Therefore, we have 3 × 2 = 6 moles of aluminum atoms and 3 × 3 = 9 moles of oxygen atoms.
For aluminum, this will be 6 moles × 6.022 × 1023 atoms/mole = 3.6132 × 1024 aluminum atoms.
For oxygen, it will be 9 moles × 6.022 × 1023 atoms/mole = 5.4198 × 1024 oxygen atoms.
To get the total number of atoms, add the number of aluminum atoms and oxygen atoms:
3.6132 × 1024 + 5.4198 × 1024 = 9.033 × 1024 atoms.