Question

Lithium nitride reacts with water to produce ammonia and lithium hydroxide according to the equation, Li3N(s) + 3H2O (L) --> NH3(g) + 3LiOH (aq) Heavy water is water with the isotope deuterium in place of ordinary hydrogen, and its formula is D2O. The above reaction can be used to produce heavy ammonia, ND3(g), according to the equation, Li3N(s) + 3D2O (L) --> ND3(g) + 3LiOD (aq) Calculate how many grams of heavy water are required to produce 160.0 mg of ND3(g). The mass of deuterium, D, is 2.014 g/mol.

Answer 1

Answer:

0.480 grams

Explanation:

Li₃N(s) + 3D₂O (L) --------------------------> ND₃(g) + 3LiOD (aq)

1             :  3                                            : 1           :  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  x 0.007983 moles

=  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