7.What is the chemical formula for Beryllium Nitride? *

How many liters of hydrogen gas will be produced at stp from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phosphoric acid (h3po4) the equation is 3mg + 2h3(> mg(po4)2+3h2

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Iron (fe) reacts with copper sulfate (cuso4) to form iron (ii) sulfate. in this reaction, cu2+ gains electrons to form cu. which statement is true about this reaction? fe(s) + cuso4(aq) → feso4(aq) + cu(s)