In: Chemistry
4)Calculate the Ecell of: Al(s) + Cu2+(aq)(0.010M) → Al3+(aq)(1.0M) + Cu(s) (is this balanced?)
A. 2.06 B. 1.94 C. -2.06
5)Calculate the Eocell for: Fe(s) + Br2(g) → Fe2+(aq) +Br-(aq) ; is this electrolytic or voltaic?
A.-1.52V ; voltaic B.1.52V ; electrolytic C.1.52V ; voltaic D.-1.52V ; electrolytic
6)Calculate the Ecell of: Au(s) ; Au3+(aq) // Sn2+(aq) ; Sn(s) is this electrolytic or voltaic?
A.1.64 ; electrolytic B.1.64 ; voltaic C.-1.64 ; voltaic D.-1.64 ; electrolytic
there are three questions. The data of electrode potential are not given with question so i am using symbols, calculation has to been done at your end using the electrode potential values.
4) its not balanced . the balanced equation is as follows :
2Al(s) +3 Cu2+(aq)(0.010M) → 2Al3+(aq)(1.0M) + 3Cu(s)
Ecell = EoCell - 0.0591/6log(Al+3)2/ (Cu2+)3
= EoCell - 0.0591/6log(1)2/ (0.01)3
= EoCell - 0.0591x6/6 = EoCell -0.0591 volt
= (1.662 + 0.337 ) -0.0591 = 1.94 volt
5) Fe(s) + Br2(g) → Fe2+(aq) +2Br-(aq)
Eocell = (Eo Fe/Fe2+ )anode + (Eo Br2/Br-1 )cathode
= 0.44 + 1.066 = 1.5 voltaic
6) its a not avoltacic cell as its represented in wrong order.
the balanced reaction is as folows :
Sn should be anode and gold electrode should be cathode .
The Eocell = (EoAu/Au+3 )anode + (EoSn+2/Sn)cathode
= 1.53 + -0.13 = 1.4 volt