The answer is 3.03 g
Ar(H) = 1.01 g/mol
Since there are three atoms in Al(OH)3, the total atomic mass of hydrogen in Al(OH)3 is:
3 * Ar(H) = 3 * 1.01 g/mol = 3.03 g/mol
The mass (m) is atomic mass (Ar) divided by the number of moles n):
m = Ar/n
Ar = 3.03 g/mol
n = 1 mol
m = 3.03 g/mol / 1 mol = 3.03 g
