Verified answer

               0,01 моль                         m=?
HCOOH  + Ag2O  = CO2 + H2O + 2Ag

              n= 1 моль                        n=2 моль

                                                    М = 108 г/моль

                                                    m= 216 г

0,01 моль Ag2O     -    X г Ag

1 моль Ag2O         -   216 г Ag

m(Ag) = 0,01 * 216 = 2,16 г