Question

1. We will be building a Cu? and Zn galvanic cell. Write the two half reactions (one as a reduction and one as an oxidation based on forming a spontaneous reaction) and write the combined reaction. (Similar to equations 9.3-9.5 but for our system specifically). (3 pts) In the galvanic cell we are building in class, which is the anode and which is the cathode? (2 pts) 2. Calculate Ecel for our voltaic cell. (Use Table 16.1 in your OpenStax (Atoms First) textbook) (2 pts) 3.

Answer 1

(1)

Anode reaction (oxidation half cell) : Zn(s) $\rightarrow$ Zn²⁺(aq) + 2 e^-

Cathode reaction (reduction half cell) : Cu²⁺(aq) + 2e^-$\rightarrow$ Cu(s)

Net cell reaction :

Zn(s) + Cu²⁺(aq) $\rightarrow$ Cu(s) + Zn²⁺(aq)

(2)

Oxidation takes place at anode so Zn|Zn²⁺ electrode is anode and reduction takes place at cathode so Cu²⁺|Cu electrode is cathode .

(3)

E°_cell = standard reduction potential of Copper - standard reduction potential of Zinc = 0.34V -(-0.76V) = 1.10 V

E_cell = E°_cell - 0.059/n ×log([Cu²⁺]/[Zn²⁺])

n =2 , E°_cell = 1.10 V