To calculate the atomic mass of Fe(OH)₃, we need to consider the components:
- The mass of iron (Fe): 56 amu
- The mass of oxygen (O): 16 amu; since there are 3 hydroxide (OH) groups in Fe(OH)₃, we have:
- 3 oxygen atoms: \( 3 \times 16 \) amu = 48 amu
- The mass of hydrogen (H): 1 amu; again, since each hydroxide contributes 1 hydrogen atom and there are 3 hydroxide groups:
- 3 hydrogen atoms: \( 3 \times 1 \) amu = 3 amu
Now, we can add these together:
\[ \text{Total atomic mass of Fe(OH)₃} = \text{mass of Fe} + \text{mass of O} + \text{mass of H} \]
\[ = 56 , \text{amu} + 48 , \text{amu} + 3 , \text{amu} \] \[ = 56 + 48 + 3 = 107 , \text{amu} \]
Therefore, the atomic mass of Fe(OH)₃ is 107 amu.