Lithium nitride reacts with water to produce ammonia and lithium hydroxide according to the equation Li 3 N ( s ) + 3 H 2 O ( l ) ⟶ NH 3 ( g ) + 3 LiOH ( aq ) Heavy water is water with the isotope deuterium in place of ordinary hydrogen, and its formula is D 2 O . The same reaction can be used to produce heavy ammonia, ND 3 ( g ) , according to the equation Li 3 N ( s ) + 3 D 2 O ( l ) ⟶ ND 3 ( g ) + 3 LiOD ( aq ) Calculate how many grams of heavy water are required to produce 455.0 mg ND 3 ( g ) . The mass of deuterium, D , is 2.014 g/mol.

The mass of needed is 1.36 grams

Explanation:

To calculate the number of moles, we use the equation:

    .....(1)

For :

Given mass of = 455.0 mg = 0.455 g   (Conversion factor:  1 g = 1000 mg)

Molar mass of = 20.049 g/mol

Putting values in equation 1, we get:

For the given chemical equation:

By Stoichiometry of the reaction:

1 mole of is produced from 3 moles of

So, 0.0227 moles of will be produced from =

Now, calculating the mass of from equation 1, we get:

Molar mass of = 20.027 g/mol

Moles of = 0.0681 moles

Putting values in equation 1, we get:

Hence, the mass of needed is 1.36 grams

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answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.