J.R. S. answered 03/14/21
Ph.D. University Professor with 10+ years Tutoring Experience
Mg+ Cu(NO3)2 ==> Mg(NO3)2 + Cu ... balanced equation
Since Cu(NO3)2 is in excess, the Mg will determine the theoretical yield.
119.6 g Mg x 1 mol Mg/24.3 g x 1 mol Mg(NO3)2 / 1 mol Mg x 148 g Mg(NO3)2/mol = 728.4 g Mg(NO3)2
At an efficiency of 47.30%, the actual yield would be...
728.4 g x 0.4730 = 344.5 g