#### Electrochemistry - Tri

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Electrochemistry - Tri

ELECTROCHEMISTRY
Kristin Shepard
Brooke Petersen
ELECTROCHEMICAL CELLS- TERMS
Electrode- Any cell that is used to conduct
electricity; Where the reaction actually takes placeSolid Part
Anode- Solid where the oxidizing happens
Cathode- Solid where the reduction occurs
Current- The flow of electrons- Electricity
Salt Bridge- Concentrated salt solution with ions
that will not react with solutions
STANDARD CELL POTENTIAL
Standard Cell Potential is known as E°
There are four simple steps
1.
2.
3.
4.
Even the electrons
Flip the most negative equation
Add the equations
Add the E°
CALCULATING ∆G°
To calculate this, we use the following equation
when all substances are at standard conditions
∆G°= -nFE°
CALCULATING K
After finding the ∆G°, we can now find K using:
∆G°= -RTlnK
HOW MANY MOLS OF PT MAY BE DEPOSITED ON
THE CATHODE WHEN 0.80 F OF ELECTRICITY IS
PASSED THROUGH A 1.0 M SOLUTION OF PT4+ ?
(A)1.0
mol
(B)0.60 mol
(C)0.20 mol
(D)0.80 mol
(E)0.40 mol
It takes 4 mol of electrons (4F)
to change the platinum ions to
platinum metal. The
calculation would be: (0.80)(1
mol Pt/4 F)= 0.20 mol Pt.
WHAT HAPPENS TO THE CELL VOLTAGE WHEN
THE COPPER ELECTRODE IS MADE SMALLER?
(A)
(B)
(C)
(D)
(E)
There is no change in the voltage.
The voltage becomes zero.
The voltage increases.
The voltage decreases, but stays positive.
The voltage becomes negative.
The size of the electrode is not important.
WHAT HAPPENS TO THE CELL
VOLTAGE AFTER THE CELL HAS
OPERATED FOR
(A)
(B)
(C)
(D)
(E)
10 MINUTES?
There is no change in the voltage.
The voltage becomes zero.
The voltage increases.
The voltage decreases, but stays positive.
The voltage becomes negative.
As the cell operates, the copper ion concentration would
decrease and the zinc ion concentration would increase. Both
of these changes would make the logarithm term in the Nernst
equation more negative. This would decrease the voltage.