Chem7

Question 1

What is the primary energy conversion in a galvanic cell?

Answer 1

Chemical energy → Electrical energy (spontaneous redox).

Question 2

Calculate E.M.F. for a cell with E°(cathode) = +0.34V (Cu²⁺/Cu) and E°(anode) = −0.76V (Zn²⁺/Zn).

Answer 2

E.M.F. = 0.34V − (−0.76V) = +1.10V (spontaneous).

Question 3

If a Daniell cell produces 2A for 1 hour, calculate charge (Q).

Answer 3

Q = I×t = 2A × 3600s = 7200 C.

Question 4

Why does a galvanic cell need a salt bridge?

Answer 4

To maintain charge neutrality by ion flow between half-cells.

Question 5

Anode polarity in galvanic vs. electrolytic cells.

Answer 5

Galvanic: −ve (oxidation); Electrolytic: +ve (oxidation).

Question 6

Example of an electrolytic cell process.

Answer 6

Electroplating or aluminum extraction (non-spontaneous, external power).

Question 7

Why is the cathode +ve in a galvanic cell but −ve in an electrolytic cell?

Answer 7

Galvanic: Reduction draws electrons (−ve pole); Electrolytic: External power forces reduction at −ve pole.

Question 8

Which cell type has E.M.F. < 0?

Answer 8

Electrolytic (non-spontaneous, requires energy input).

Question 9

List 3 galvanic cell examples.

Answer 9

Daniell cell, lead-acid battery, mercury cell.

Question 10

What happens to graphite anodes in aluminum extraction?

Answer 10

They erode: 2C + ³⁄₂O₂ → CO + CO₂.

Question 11

Why can electrolytic cells use identical electrodes?

Answer 11

External power drives the reaction; no need for different materials.

Question 12

Compare E.M.F. signs for both cell types.

Answer 12

Galvanic: +ve (spontaneous); Electrolytic: −ve (non-spontaneous).