(1)①前面 ② R Fe Cu
(2)Fe 2O 3+ 6HCl = 2FeCl 3+ 3H 2O 125
(3)①Ag
②Cu+2AgNO 3=2Ag+Cu(NO 3) 2Zn+Cu(NO 3) 2=Cu+Zn(NO 3) 2(2分,各1分)