Answer
3.725 x $10^{-1}$ g.
Work Step by Step
1. Find the molar mass of Ammonium Phosphate $(N_{}H_{4})_{3}P_{}O_{4}$.
N: 14 x 3 = 42
H: 1 x 12 = 12
P: 31 x 1 = 31
O: 16 x 4 = 64
42 + 12 +31 + 64 = 149g/mol
2. Multiply the number of mols by the molar mass of the molecule:
2.5 x $10^{-3}$ x 149 = 372.5 x $10^{-3}$ = 3.725 $10^{-1}$g.
