Question

Calculate the standard emf of a cell that uses the Mg/Mg2+ and Cu/Cu2+ half-cell reaction at 25°C. E o = V Write the equation for the cell reaction that occurs under standard-state conditions. Be sure to include the physical state of each species in the reaction.

Answer 1

Answer with Explanation:

We have to calculate the standard emf of a cell.

Consider
`E^0_(Mg/Mg+2)=-2.37 v`

`E^0_(Cu/Cu+2)=0.34 V`

T=
`25^(\circ)=25+273=298 K`

Anode half reaction:
`Mg(s)\rightarrow Mg+2(aq)^+2e-`

Cathode half reaction:
`Cu+2(aq)+2e-\rightarrow Cu(s)`

Overall reaction of cell :

`Mg(s)+Cu+2(aq)\rightarrow Mg+2(aq)+Cu(s)`

Cathode :The electrode which gains electrons.

Anode: The electrode which losses electrons.

We know that standard emf of the cell

`E^0_(cell)=E_(cathod)-E_(Anode)`

`E^0_(cell)=0.34+2.37=2.71 V`

Hence, the standard emf of a cell=2.71 V