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

To produce 160mg of ND3, 479mg of D2O (heavy water) is required, as calculated using molar masses and stoichiometric relationships in the balanced chemical equation.

Step-by-step explanation:

To answer the question, firstly, we need to calculate the molar mass of ND3 (g). Since Nitrogen has a molar mass of 14.007 g/mol and Deuterium (D) has a molar mass of 2.014 g/mol, the molar mass of ND3 will be 14.007 g/mol + (3 x 2.014 g/mol) = 20.049 g/mol. To proceed further, we have to convert the given mass of 160 mg (0.160 g) of ND3 to moles. Moles = Mass/Molar Mass = 0.160 g / 20.049 g/mol = 0.00798 mol.

From the balanced chemical equation, we know that 3 moles of D2O are required to produce 1 mole of ND3. Therefore, to produce 0.00798 mol of ND3, it will require 0.00798 mol x 3 = 0.0239 mol of D2O. D2O has a molar mass of 20.0276 g/mol. Hence, the required mass of D2O = 0.0239 mol x 20.0276 g/mol = 0.479 g or 479 mg.

Learn more about Stoichiometry and Molar Mass calculations

Answer 2

0.480 grams

Step-by-step 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