Answer:
[tex]\boxed {\boxed {\sf 101.96 \ amu}}[/tex]
Explanation:
Formula mass is the sum of the atomic masses of the atoms in a molecule. Essentially, it is the mass of 1 molecule of a compound.
We are given a compound containing 2 aluminum atoms and 3 oxygen atoms. We will use the Periodic Table to look up the atomic masses of the 2 elements in the compound.
These are the atomic masses of 1 atom of the element. Remember we have 2 Al atoms and 3 O atoms. We multiply the element's atomic mass by the number of atoms of that element in the compound.
Now we add the atomic mass of 2 Al atoms and 3 O atoms.
We may want to round this answer to the hundredth place. The 0 in the thousandth place tells us to leave the 6 in the hundredth place.
The formula mass of a compound with 2 aluminum atoms and 3 oxygen atoms is approximately 101.96 atomic mass units.
