What is the weight in grams of silver displaced by 0.1 mole of magnesium?

1 Answer
Mar 24, 2018

215.736 grams.

Explanation:

Magnesium metal displaces silver from an aqueous solution according to the formula
Mg (s) +2Ag^+ (aq) ->Mg^(2+) (aq) +2Ag (s)

Thus (n(Ag))/(n(Mg))=2/1
n(Ag)=n(Mg)*(n(Mg))/(n(Ag))=0.1*2/1=0.2*"mol"

M(Ag)=107.868 g*mol^(-1) from the periodic table. Therefore
m(Ag)=n(Ag)*M(Ag)=215.736*g

Note how the charge conserves on either side of the equation. The conservation of charge can be something helpful to refer to in case you forget the ratio during an exam. As an alkaline-earth metal (i.e., of the second column of the periodic table from the left) magnesium ion would have a charge of +2 in solution. Still, you need to memorize that most silver ions in an aqueous solution have oxidation state +1.