This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: 1 If you were going to construct a Galvanic cell using Cu 2+ /Cu and Hg 2+ /Hg a) Which would be the cathode b) Which would be the anode c) What would the cell potential ( cell ) be? d) What reaction occurs at the cathode? e) What reaction occurs at the anode? f) What is the net redox reaction? g) How many electrons are transferred? h) Which way do the cations in the salt bridge migrate? i) Which way to the anions in the salt bridge migrate? j) Which electrode gets smaller as the rxn progresses? Section 11.4 Step 1: Look up the reactions in Table 11.1. List them with most negative on top, and most positive on bottom. Hg 2+ (aq) + 2e- Hg(l) +0.85 V Cu 2+ (aq) + 2e- Cu(s) +0.34 V Step 2: The anode is always on the top (most negative). The cathode is always on the bottom (most positive). Section 11.4 cathode anode Step 3: E cell = E cat- E an E cell = +0.85 V (+0.34V ) = +0.51V Step 4: The bottom reaction can be left alone, because reduction occurs at the cathode. The top reaction must be reversed, because oxidation occurs at the anode. Hg 2+ (aq) + 2e- Hg(l) +0.85 V Cu 2+ (aq) + 2e- Cu(s) +0.34 V Section 11.4 cathode anode Hg 2+ (aq) + 2e- Hg(l) Cu(s) Cu 2+ (aq) + 2e- Cathode rxn Anode rxn Hg 2+ (aq) + 2e- Hg(l) Cu(s) Cu 2+ (aq) + 2e- Hg 2+ (aq) + Cu(s) Hg(l) + Cu 2+ (aq) Cathode Anode Step 5: Add the two rxns together in such a way that the electrons cancel out. This is the net redox reaction. Step 6: The number of electrons needed on each side to balance the redox reaction is the number of electrons transferred. Note: If you put the components to the bottom (cathode) reaction first on each side, youll have put the oxidizing agent first. 2 Section 11.4 Hg 2+ (aq) + 2e- Hg(l) Cu(s) Cu 2+ (aq) + 2e- Step 7: Put the reactions with a picture of a battery....
View Full Document