How many molecules of lithium nitride must react in order to produce 24.7g of strontium phosphate?

Answer 1

From your previous question, I believe you meant to ask how many molecules of lithium nitride must react in order to produce 24.7 g of strontium nitride (not strontium phosphate. If that's the case, perhaps you should re-submit the question in the correct form. As currently written, it makes no sense.