Respuesta :
Answer:
0.480 grams
Explanation:
Li₃N(s) + 3D₂O (L) --------------------------> ND₃(g) + 3LiOD (aq)
1 Â Â Â Â Â Â : Â 3 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â : 1 Â Â Â Â Â : Â 3
Number of moles (n) = Mass in gram/ Molar Mass
Mass of ND₃ = 160 mg
           = 0.16 g
Molar mass of ND₃=  [14 + (3 x 2.014 )]
                =   14 + 6.042
                =  20.042 g/mol
Number of moles of  ND₃  =  0.16/20.042
                       =  0.007983 moles
From the reaction equation, the mole ratio between  Heavy water (D₂O ) and  ND₃ is  3: 1.
This implies that the number of moles of  Heavy water (D₂O )  required
= 3 Â x 0.007983 moles
= Â 0.023949 moles
Molar mass of  Heavy water (D₂O )=  [(2.014 x 2) + 16]
                              =  20.028 g/mol
Mass in grams of Heavy water (D₂O )= Number of moles  x Molar mass
                              =  0.023949  x  20.028
                              =  0.4797 grams
                              ≈ 0.480 grams