Answer to Question #166850 in Chemistry for Luelsegedkumsa

Question

1. If 75ml of AgNO3 solution reacts with enough Cu to produce 0.25g of Ag by single displacement, what is the molarity of the initial AgNO3 solution ?for the reaction AgNO3+Cu=Cu(NO2)2+Ag

Answer 1

Solution:

The balanced chemical equation:

2AgNO₃ + Cu → Cu(NO₃)₂ + 2Ag

According to the equation above: n(AgNO₃) = n(Ag)

Moles of Ag = Mass of Ag / Molar mass of Ag

The molar mass of Ag is 107.8682 g mol^-1.

Hence,

n(Ag) = 0.25 g / 107.8682 g mol^-1 = 0.00232 mol

n(AgNO₃) = n(Ag) = 0.00232 mol

Molarity of AgNO₃ = Moles of AgNO₃ / Volume of AgNO₃ solution

Molarity of AgNO₃ = 0.00232 mol / 0.075 L = 0.0309 mol/L = 0.0309 M

Molarity of AgNO₃ = 0.0309 M

OR:

(0.25 g Ag / 75×10^-3 L soln.)×(1 mol Ag / 107.8682 g Ag)×(2 mol AgNO₃ / 2 mol Ag) = 0.0309 M AgNO₃

Answer: The molarity of the initial AgNO₃ solution is 0.0309 M.