Uranium, most uranium does derive from a star. However, not from our sun.
This problem is providing the chemical reaction whereby barium nitride reacts with water to produce barium hydroxide and ammonia, so the number of moles of barium nitride are required in order to produce 8.3 moles of ammonia. It asks for us to evaluate the student's setup, so we conclude the answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3", according to:
<h3>Mole ratios:</h3>
In chemistry, stoichiometric calculations are used to figure out the moles or mass of a substance, given information about another one in the reaction. In this case, for the given chemical equation:

We evidence a 1:2 mole ratio of barium nitride to ammonia, for that reason, the student's setup:

Is incorrect, because the ammonia must be accompanied by a 2 rather than the 1 it is given there:

Thereby, the correct answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3"
Learn more about mole ratios: brainly.com/question/15288923
Answer: C.
This is because the atoms on either side of the equation in all the other solutions are not equal.
I dont know the answer but i have some explanation for that question.
Since krypton is in the far right row of the periodic table, its outermost shell is full with eight electrons. This is one of the happy elements and has an electron configuration of 2-8-18-8.