(1)根據(jù):Cu+4HNO3=Cu(NO3)2+2NO2↑+2H2O
3Cu+8HNO3=3Cu(NO3)2+2NO↑+4H2O
Ag+2HNO3=AgNO3+NO2↑+H2O
3Ag+4HNO3=3AgNO3+NO↑+2H2O
可知:被還原的n(HNO3)=n(NO2)+n(NO)=6.72L/22.4L/mol=0.3mol
(2)由題意可知:反應(yīng)后的溶液中c(HNO3)=1mol/L
反應(yīng)中消耗:
n(HNO3)=0.3mol+2n(Cu(NO3)2)+n(AgNO3)
=0.3mol+2n(Cu)+n(Ag)
=0.08L*(13.5mol/L-1mol/L)=1mol
則:2n(Cu)+n(Ag)=0.7mol
又據(jù):64n(Cu)+108n(Ag)=30
解得:n(Cu)=0.3mol; n(Ag)=0.1mol
合金中銀的質(zhì)量分?jǐn)?shù)=0.1*108/30=36%