Corban E. answered 11/13/20
AP Chemistry Tutor and Former Teacher (Gen Chem, IB, O-Level, A-Level)
Ni+2AgNO3→Ni(NO3)2+2Ag
21.5g Ni/58.69g =0.366mol Ni
Ag=107.87
Ni=58.69
But, 2molAg per 1 mol Ni, so, change in mass is more like...
twice as many moles Ag as Ni, and then mass relationship is 107.87gAg/58.69, but due to the 2Ag:1Ni mol ratio, the change in mass is like:
107.87(2)/58.69=3.68 times increase
So, final mass of Ag is 3.68x, and the change in mass of Ni is x
36.5=(21.5-x)+(3.68x)
solve for x
x=5.597
3.68x=g Ag
3.68(5.597)=20.59
21.5-x=g Ni after reaction
21.5-5.597=15.903g Ni
20.59gAg+15.903g Ni=36.5g metal


J.R. S.
11/14/20
Corban E.
11/13/20