Unit 4

Question 1

Voltaic/galvanic cell

Answer 1

Cathode (+) higher E°
Anode (-) lower E°
🔺G < 0
E°cell > 0
Spontaneous

Question 2

Electrolytic cell

Answer 2

Cathode (-) lower E°
Anode (+) higher E°
🔺G > 0
E°cell < 0
Non-spontaneous

Question 3

Voltaic/galvanic and electrolytic similarities

Answer 3

Reduction at cathode, gain e-
Oxidation at anode, lose e-
Anions go to anode
Cations go to cathode

Question 4

How many M Al3+ in 0.2 M Al2(SO4)3?

Answer 4

0.4 M

Question 5

Relating Cell Potential and Free Energy

Answer 5

🔺G° = -n * F * E°cell

Question 6

Relating Cell Potential and Equilibrium Constant, K

Answer 6

E°cell = (.0591 / n) * log(K)

Question 7

Relating Free Energy and Equilibrium Constant, K

Answer 7

🔺G° = -R * T * ln(K)

Question 8

Spontaneous Reaction cell type? Ecell? 🔺G? K?

Answer 8

Voltaic/galvanic
Ecell > 0
🔺G < 0
K > 1

Question 9

Equilibrium Ecell? 🔺G? K?

Answer 9

Ecell = 0
🔺G = 0
K is a constant. When it’s at equilibrium, Q = K. K is whatever it was before. K doesn’t change when it reaches equilibrium. Q changes value but K doesn’t.

Question 10

Non-spontaneous Reaction cell type? Ecell? 🔺G? K?

Answer 10

Electrolytic
Ecell < 0
🔺G > 0
K < 1

Question 11

The Nernst Equation

Answer 11

Ecell = E°cell - ((0.0591 / n) * log(Q))

Question 12

Anode and cathode in concentration cell?

Answer 12

Anode = less concentrated solution = oxidized
Cathode = more concentrated solution = reduced