{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CHhmwk8 - moore(jwm2685 Homework 8 vanden bout(51640 This...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
moore (jwm2685) – Homework 8 – vanden bout – (51640) 1 This print-out should have 37 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. ******Note: You will need a table of stan- dard reduction potentials to complete this homework assignment. These can be found online, as well as in your textbook.********* 001 10.0points Sodium is produced by electrolysis of molten sodium chloride. What are the products at the anode and cathode, respectively? 1. O 2 (g) and Na( ) 2. Cl 2 (g) and Na 2 O( ) 3. Cl 2 (g) and Na( ) correct 4. Cl (aq) and Na 2 O( ) 5. Na( ) and O 2 (g) Explanation: 002 10.0points What is the standard cell potential of the strongest battery that could be made using these half reactions? Br 2 + 2 e -→ 2 Br Fe 3+ + 3 e -→ Fe Co 3+ + e -→ Co 2+ Zn 2+ + 2 e -→ Zn E = +1 . 07 E = - 0 . 04 E = +1 . 80 E = - 0 . 76 1. 1.84 2. 1.03 3. 1.11 4. 2.56 correct 5. 1.83 6. 1.04 Explanation: The strongest reducing agent is Co 3+ and the strongest oxidizing agent is Zn. The stan- dard cell potential of a battery built from these species would be: E cell = E cathode - E anode = 1 . 80 -- 0 . 76 = 2 . 56 003 10.0points Which metal will dissolve in hydrochloric acid? 1. Au 2. Pt 3. Ag 4. Fe correct 5. All will dissolve. Explanation: 004 10.0points What would be the E cell of an electrolytic cell made from the following two half reac- tions? Half reaction E AgCl( s ) + e -→ Ag( s ) + Cl ( aq ) +0 . 22 Al 3+ ( aq ) + 3 e -→ Al( s ) - 1 . 66 1. - 1 . 44 2. 1 . 88 3. 1 . 44 4. - 1 . 88 correct Explanation: E = E cathode - E anode = - 1 . 66 - 0 . 22 = - 1 . 88 005(part1of3)10.0points The galvanic cell below uses the standard half-cells Mg 2+ | Mg and Zn 2+ | Zn, and a salt bridge containing KCl(aq). The voltmeter
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
moore (jwm2685) – Homework 8 – vanden bout – (51640) 2 gives a positive voltage reading. - + A B voltmeter D C E F Salt Bridge Identify A and write the half-reaction that occurs in that compartment. 1. Mg(s); Mg 2+ (aq) + 2 e Mg(s) 2. Zn(s); Zn 2+ (aq) + 2 e Zn(s) 3. Mg(s); Mg(s) Mg 2+ (aq) + 2 e cor- rect 4. Zn(s); Zn(s) Zn 2+ (aq) + 2 e Explanation: 006(part2of3)10.0points What happens to the size of the electrode A during the operation of the cell? 1. decreases correct 2. No change 3. increases Explanation: 007(part3of3)10.0points What is the voltmeter reading? 1. +3.40 V 2. +4.30 V 3. +0.50 V 4. +1.60 V correct 5. +2.50 V Explanation: 008 10.0points For any voltaic cell which produces electrical energy available to do external work, which of the following statements is always true? 1. The change in Gibbs free energy for the overall cell process must be negative. 2. The cathode is the positive electrode. 3. Oxidation takes place at the anode. 4. All of the other answers listed are correct. correct 5. The overall cell potential must be posi- tive. Explanation: 009 10.0points A steel surface has been electroplated with 5.10 g of vanadium (V, molar mass = 51 g/mol). If 2.90 × 10 4 C of charge were used, what was the original oxidation number of V?
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}